E  ACTIVATED  SLUDGE  PROCESS 
OF  SEWAGE  TREATMENT 


A  Bibliography  of  the  Subject 


With  Brief  Abstracts,  Patents,  News  Items,  Etc., 

Compiled  Mainly  from  Current  Literature. 

Second  Edition,   1921 

-JFORNIA 
;VIL   ENGINEER!  N- 


F  CALIFORNIA 
NT  OF  CIVIL  ENGINEE 
:KELEV  41* 

By  J.  EDWARD  PORTER 

Consulting  Chemical  Engineer 

General  Filtration  Co.,  Inc. 

ROCHESTER,  N.  Y. 


Copyright  1921  by  General  Filtration  Co.,  Inc. 


PRICE  $1.00 


THE  ACTIVATED  SLUDGE  PROCESS 
OF  SEWAGE  TREATMENT  '-:- 


A  Bibliography  of  the  Subject 


With  Brief  Abstracts,  Patents,  News  Items,  Etc., 

Compiled  Mainly  from  Current  Literature. 

Second  Edition,   1921 


By  J.  EDWARD  PORTER 

Consulting  Chemical  Engineer 

General  Filtration  Co.,  Inc. 

ROCHESTER,  N.  Y. 


>?*/ 


•':  •'•:•  G":ii ..;  .FOREWORD 


IN  compiling  this  bibliography,  an  attempt 
has  been  made  to  arrange  the  matter  in 
chronological  order.  The  first  periodical 
reference  for  each  abstract  is  supposed  to 
indicate  the  first  appearance  of  the  article 
in  print,  though  not  necessarily  the  full  pa- 
per, as  proceedings,  transactions,  annual  re- 
ports, etc.,  which  contain  it  are  often  issued 
many  months  later.  The  subsequent  period- 
ical references  under  the  same  abstract  may 
be  either  the  original  article,  a  reprint  or 
an  abstract  of  it.  Publications  appearing 
monthly  are  credited  with  issue  on  the  first 
of  the  month,  annual  reports,  transactions, 
etc.,  are  placed  at  the  end  of  the  year  in  which 
the  document  is  dated.  The  periodical  index 
at  the  end  gives  the  date  of  publication  cor- 
responding to  the  volume  and  page  number. 

While  there  are  doubtless  some  omissions, 
an  effort  has  been  made  to  make  this  revision 
of  the  bibliography  complete  from  the  be- 
ginning to  the  end  of  1920,  the  compiler  not 
attempting  to  define  "the  beginning"  of  the 
activated  sludge  process  proper,  further  than 
to  insert  as  the  first  reference  the  earliest 
article  relating  to  the  subject  which  has  come 
to  his  attention.  At  all  events  it  is  believed 
that  the  compilation  will  be  found  useful  to 
Sanitary  Engineers  and  others  interested  in 
sewage  disposal. 

Indebtedness  is  acknowledged  to  Prof.  Ed- 
ward Bartow,  Professor  of  Chemistry  and 
Head  of  the  Department  of  Chemistry,  State 
University  of  Iowa;  to  Dr.  F.  W.  Mohlman, 
Chief  Chemist  for  the  Chicago  Sanitary  Dis- 
trict, and  to  Mr.  T.  Chalkley  Hatton,  Chief 
Engineer,  Milwaukee  Sewerage  Commission, 
for  valuable  assistance  given. 

January,  1921. 

d 


=*" 


Nomenclature  and  Definitions 


NOMENCLATURE  CONCERNING  THE  ACTIVATED  SLUDGE  PROCESS 

OF  SEWAGE  DISPOSAL  AS  SUGGESTED  BY  F.  A.  DALLYN,  GEO. 

T.  HAMMOND   AND   T.   CHALKLEY   HATTON,   A   COMMITTEE 

APPOINTED    FOR    SUCH    PURPOSE    AT    AN    INFORMAL 

MEETING  OF  MEMBERS  OF  THE  AM.  SOC.  C.  E.  AND 

OTHERS     INTERESTED     IN     SEWAGE     DISPOSAL, 

HELD  AT  PITTSBURGH,  JUNE,  1916. 


(Revised  December,  1920) 


DEFINITIONS 

1.  Activated  sludge  treatment  miay  be  defined  as  a  biochemical  process 
by  which  the  purification  of  sewage  is  accomplished  by  passing  it  through 
tanks,  in  which  sewage  sludge  is  artificially  agitated  and  intimately  mixed 
with  sewage  and  is  supplied  with  the  requisite  oxygen  for  the  optimum  develop- 
ment of  countless  numbers  of  nitrifying  organisms  incorporated  in  and  ad- 
hering to  the  sludge,  the  final  settlement  of  which  causes  a  distinct  clarifica- 
tion of  the  oxidized  sewage. 

2.  Activated  sludge  may  be  defined  as  a  flocculent  sludge  of  medium 
brown  color  enveloped  by  masses  of  aerobic  organisms  possessing  the  power 
of  rapidly  oxidizing  and  nitrifying  sewage,  and  which,  though  of  low  specific 
gravity,  settles  rapidly. 

3.  The  process  may  be  divided  into  the  following  treatments: — 

(a)  Economic  screening. 

(b)  Preliminary  rapid  sedimentation  in  properly  designed  grit  chambers 

where  combined  flow  of  sewage  and  storm  water  must  be  treated. 
It  being  quite  essential  to  prevent  detritus  of  heavy  specific  grav- 
ity, such  as  sand  and  gravel,  from  reaching  the  treatments  which 
follow. 

(c)  Thorough  mixing  in  aerating  the  sewage  with  activated  sludge,  which 

may  be  effected  by  means  of  air,  by  mechanical  mixers,  or  a  com- 
bination of  both.  In  any  case  sufficient  air  for  oxidation  must  be 
applied  to  the  admixture. 

(d)  Sedimentation  of  the  sludge  contained  in  the  admixture  as  it  passes 

from  the  aerating  tank.  This  may  be  accomplished  by  either 
horizontal  or  vertical  flow  sedimentation  tanks. 

(e)  The  return  of  a  portion  of  the  settled  activated  sludge  to  the  raw 

sewage  before,  or  at  the  time,  it  enters  the  aerating  tank. 

(f)  Reaerating  the  sludge  which  is  returned  to  the  raw  sewage  in  sep- 

arate aerating  tanks.  This  may  or  may  not  be  necessary,  depend- 
ing upon  the  character  of  the  sewage  treated  and  effluent  required. 

(g)  Secondary    sedimentation    for    partially    dewatering    the    separated 

sludge  not  returned  to  the  raw  sewage. 


447714 


The  Activated  Sludge  Process 

(h)  Sludge  disposal.  This  may  be  effected  in  several  ways.  Where  the 
climatic  conditions  are  favorable,  it  may  be  dried  in  beds  or 
lagoons  in  the  open  air  or  under  cover,  and  the  residue  used  for 
filling  in  low  ground,  or  for  fertilizer,  or  burned.  Under  un- 
favorable climatic  conditions  it  may  be  pressed  or  centrifuged 
and  burned,  or  dried  by  artificial  heat  and  the  residue  used  as 
fertilizer. 

The  terms  used  in  connection  with  the  process  may  be  defined  as  follows: 

4.  Screening.     Such  as  may  be  the  most  economical  under  the  existing 
conditions.    Probably  through  from  one-eighth  to  one-sixteenth  inch  screen. 

5.  Grit.    That  portion  of  the  mineral  solids  carried  in  the  sewage  liquor 
which  will  settle  out  under  a  velocity  of  one  foot  per  second.    The  grit  chamber 
should  be  so  designed,  and  the  removal  of  the  grit  so  performed,  that  a  fairly 
uniform  velocity  through  the  chamber  may  be  maintained.     Probably  from 
0.75  to  1.25  feet  per  second.     Grit  in  the  aerating  tank  seriously  affects  the 
process. 

6.  Air.    To  be  obtained  by  means  of  a  low  pressure  compressor  or  blower, 
and  must  be  kept  free  of  oil,  grease  or  dust.    The  latter  may  be  removed  effec- 
tively by  means  of  a  standard  type  of  air  washer. 

(a)  Volume  of  air  used  should  be  expressed  as  "Air  Factor,"  obtained 

by  multiplying  the  volume-of-f  ree-air-per-volume-of  -sewage- 
treated  by  the  feet-of-air-submergence,  or  the  cubic-feet-of-air- 
per-gallon-of-sewage  by  the  pounds-of-pressure. 

(b)  Area  of  air  diffusers,  where  porous  plates  are  used,  to  be  expressed  as 

a  ratio  between  effective  square  feet  of  air  diffusers  and  square 
feet  of  water  surface  in  tank.  Where  grills  or  grids  of  pipes  are 
used,  size  of  pipe,  size  and  spacing  of  perforations,  spacing  of 
pipes  and  grids,  to  be  expressed  in  feet  and  inches.  Feet-of-air- 
submergence  should  be  noted  in  this  connection. 

(c)  Time  of  aeration  of  raw  sewage  should  be  expressed  in  hours  and 

minutes,  computed  from  the  average  period  required  for  the  mix- 
ture of  sewage  and  activated  sludge  to  pass  through  the  aerating 
tank. 

(d)  Where  the  activated  sludge  is  reaerated  after  removal  from  the  sedi- 

mentation tank,  and  before  being  returned  to  aerating  tank,  the 
air  used  for  this  purpose  should  be  separately  measured  and 
expressed  in  cubic  feet  of  air  per  gallon  of  sewage  treated  and 
added  to  the  volume  of  air  used  in  the  aerating  tanks  to  determine 
the  full  quantity  of  air  used  in  the  process,  assuming  air  is  used 
for  reaerating  at  same  pressure  as  for  aerating. 

(e)  Where  the  sludge  deposited  in  the  sedimentation  tank  is  removed  by 

an  air  lift,  the  quantity  used  should  be  separately  measured  and 
expressed  in  cubic  feet  of  free  air  per  gallon  of  sewage  treated. 
Pressure  being  considered. 

(f )  Power  used. 

7.  Activated  sludge.    Must  be  of  such  a  flocculent  character  as  to  absorb 
the  colloidal  matter  in  raw  sewage  within  a  contact  period  of  two  hours,  and 
be  of  a  golden  brown  color. 

(a)  It  is  to  be  introduced  into  the  raw  sewage  as  it  passes  into  the 
aerating  tanks,  the  air  effecting  the  mixing  as  both  pass  through 
the  tanks,  in  such  proportions  as  may  be  necessary  to  secure 
the  required  effluent  in  each  case.  Probably  from  15%  to  25%. 


Nomenclature  and  Definitions 

(b)  The  proportion  of  the  admixture  shall  be  expressed  in  percentage  of 

volume  determined  by  settlement  for  one-half  hour  in  a  gradu- 
ated one-liter  glass  cylinder  approximately  fifteen  inches  in  height 
and  two  and  one-quarter  inches  in  diameter.  It  is  also  recom- 
mended that  such  percentage  be  determined  as  parts  per  million 
of  total  dry  solids  where  facilities  for  making  such  determina- 
tions are  available. 

(c)  The  volume  of  sludge  removed  and  recovered  by  the  process  should 

be  expressed  in  pounds  per  million  gallons  of  sewage  treated, 
based  upon  the  weight  of  the  sludge  free  from  moisture.  It  is 
also  handy  to  express  the  sludge  removed  in  gallons  per  million 
gallons  of  sewage  treated,  noting  the  percentage  of  moisture  in 
the  sludge. 

8.  Sedimentation.    This  may  be  accomplished  in  either  of  two  ways: — Up- 
ward or  horizontal  flow.     If  upward  flow  is  used  the  velocity  should  be  ex- 
pressed in  feet  per  hour.    If  horizontal  flow,  express  the  velocity  in  feet  per 
minute.    Average  velocities  being  used.    Probably  the  most  certain  method  of 
expressing  rate  of  sedimentation  is  by  gallons  of  sewage  passing  through  per 
square  foot  of  tank  surface. 

(a)  The  ratio  between  the  area  of  sedimentation  tank  and  aerating  tank 
should  be  stated;  also  the  ratio  of  the  volumes  of  the  two. 

9.  Effluent.     Character  of  effluent  should  be  expressed  in  plain  biological 
chemical  and  physical  terms. 

(a)  Biologically,  in  total  bacteria  per  c.  c.  growing  for  48  hours  in  nutrient 

agar  at  20°  C.,  and  percentage  of  removal.  Also  bacteria  at 
37°  C. 

(b)  Chemically,  in  oxygen  consumed,  dissolved  oxygen,  organic  nitrogen 

and  free  ammonia  as  determined  by  the  standard  methods  recom- 
mended by  the  American  Public  Health  Association.  Stability 
in  hours  Trith  methylene  blue  without  dilution  at  70°  P. 

(c)  Physically,  in  suspended  matter  in  parts  per  million  and  in  percentage 

of  removal  from  raw  sewage.  Clarification  in  terms  of  turbidity 
determined  by  the  standard  methods  recommended  by  the  Ameri- 
can Public  Health  Association. 

10.  Capacity. 

(a)  Capacity  for  areation  should  be  expressed  in  gallons  per  acre  of  tank 

surface  per  24  hours,  stating  effective  depth  of  tanks  and  average 
contact  period. 

(b)  Capacity  for  sedimentation  should  be  expressed  in  gallons  per  square 

foot  of  tank  surface  per  24  hours,  stating  effective  depth  of  tank. 

11.  Costs.    To   be   expressed   in  million  gallons   of   sewage  treated  and 
divided)  as  follows: — 

(a)  Population  served. 

(b)  Character    of   sewage,   whether   purely    domestic,    or    domestic   and 

manufacturing,  or  combined  with  storm  water. 

(c)  Total  volume  of  sewage  treated  per  year. 

(d)  Average  daily  volume  of  sewage  treated,  with  low  and  peak  rates. 

5 


The  Activated  Sludge  Process 

(e)  Average  daily  suspended  matters  in  raw  sewage. 

(f )  High,  low  and  average  temperatures  of  sewage  and  atmosphere. 

(g)  Method  of  sludge  disposal. 

(h)  Pounds  of  sludge  produced  per  year  on  dry  basis. 

(i)    Pounds  of  sludge  produced  (on  dry  basis)  per  million  gallons  treated 
(average). 

(j)   Cost  of  sludge  disposal  per  dry  ton  produced,  including  overheads. 

(k)  Cost  of  sludge  disposal  per  million  gallons  of  sewage  treated,  includ- 
ing overheads. 

(1)    Cost  of  sewage  treatment,  including  sludge  disposal  per  million  gal- 
lons of  sewage  treated,  including  overheads. 

(m)  Total!  cost  of  plant  and  when  built. 

(n)  Fixed  annual  charges,  including  interest  and  depreciation. 

(o)  Total  operating  charges  including  ordinary  repairs. 

(p)  Total  cost  of  sewage  treatment,  including  overhead  and  fixed  charges, 
per  million  gallons  of  sewage  treated. 

Note: — Where  possible,  operating  charges  should  be  subdivided  into  cost 
of  air  furnished,  plant  labor,  sludge  disposal  labor,  and  other  charges  in 
connection  with  disposing  of  sludge. 

F.  A.  DALLYN, 
GEORGE  T.  HAMMOND, 
T.  OHALKLEY  HATTON, 

Committee. 


ABSTRACT  BIBLIOGRAPHY 


1912 

1  Experiments  upon  the  purification  of  sewage  and  water  at  the  Lawrence 
Experiment  Station.    H.  W.  CLARK  and  S.  DEM.  GAGE.    44th  Annual  Re- 
port State  Board  of  Health  of  Mass.  1912.    275-367.    In  the  sub-chapter  on  the 
aeration  of  sewage  as  an  aid  to  nitration  (pp.  290-2),  it  is  noted  that  the  aera- 
tion of  sewage  perceptibly  clarified  it,  and  that  when  green  growths  occurred 
in  the  aerated  sewage,  it  became  saturated  with  0.     These  observations  led 
to  a  series  of  experiments  begun  in  April,  1912,  to  test  the  efficiency  of  aeration 
combined  with  these  growths,  in  which  three  small  sand  filters  were  used; 
the  first  receiving  raw  sewage;  the  siecond,  sewage  aerated  for  twenty-four 
hours  by  drawing  or  blowing  air  through  it  and  the  third  containing  aerated 
sewage  with  green  growths.  It  was  found,  after  the  experiments  had  been  under 
way  for  several  months,  that  nitrification  was  occurring  in  the  aerated  sewage 
containing  the  growths,  over  1.5  parts  of  nitrate  per  100,000  being  found. 
Later  an  aerating  tank  containing  slabs  of  slate  was  put  into  operation,  in 
which  it  was  observd  that  the  slate  and  sides  of  the  tank  became  covered  with 
a  compact  brown  growth,  and  that  this  growth  collected  not  only  the  suspended 
matters,  but  also  a  large  portion  of  the  colloids,  so  that  after  a  few  hours 
treatment  the  sewage  became  free  from  both.    Tables  of  analytical  data  show- 
ing free  and  albuminoid  ammonia,  nitrates,  nitrites,  and  0  consumed  in  the 
raw  and  treated  sewage  are  given. 

1913 

2  Preliminary  note  on  the  bacterial  clarification  of  sewage.     G.  J.  FOWLER 
and  E.  M.  MUMFORD.     Jour.  Royal  Sanit.  Inst.  34,  497-500.     Surveyor  44, 

287-8.  Chem.  Abst.  7,  3632.  Laboratory  experiments  on  quantities  up  to  4 
liters  indicate  the  possibility  of  removing  the  colloidal  matter  from  sewage 
by  adding  1  grain  of  iron  salt  per  gallon,  inoculating  with  the  iron  bacterium 
"M7"  (*)  and  passing  air  through  the  liquid  for  6  hours.  A  precipitate  of 
ferric  hydrate  is  obtained  which  settles  out  in  6  hours  leaving  a  clear,  color- 
less liquid.  The  coarser  suspended  matter  must  first  be  removed. 

*  (Further  reference  to  the  iron  bacterium  "M7"  can  be  found  in 
Jour.  Chem.  Soc.  103,  645-50.  Jour.  Royal  Sanit.  Inst.  Nov.,  1913. 
Surveyor  42,  497;  45,  504-6.  Can.  Engr.  26,  598-60.  Chem.  Abst. 
7,  2770;  8,  2016.  See  also  Book  "Iron  Bacteria";  D.  Ellis,  pp.  179, 
Metheun  &  Co.,  Lt'd.,  London.  1919.) 

3  Aeration   of   sewage   and   other   foul   liquids.     W.   JONES   and   JONES   & 
ATTWOOD,  LT'D.,  Stourbridge,  Eng.     British  Patent  22,952,  Oct.  11,  1913. 

Jour.  Soc.  Chem.  Ind.  34,  244.  Chem.  Abst.  9,  831.  A  series  of  diff users  spaced 
apart  and  each  formed  of  a  porous  earthenware  plate,  on  the  under  side  of 
which  compressed  air  is  admitted,  are  arranged  transversely  across'  the  bottom 
of  each  section  of  the  tank  holding  the  sewage  to  be  aerated.  The  sewage  is 
transferred  from  one  section  of  the  tank  to  the  next  by  a  circulator  consisting 
of  an  uptake  pipe  at  the  bottom  of  which  compressed  air  is  admitted;  the  mix- 
ture of  air  and  sewage  rises  and  is  delivered  onto  the  covered  top  of  a  down- 
take  pipe,  into  which  air  is  also  admitted  below  the  water  level.  The  lower 
end  of  the  downtake  pipe  is  enlarged  to  form  a  foot  chamber,  where  the  excess 
of  air  escapes  and  is  passed  on  to  supply  the  diffusers,  while  the  sewage  passes 
into  the  bottom  of  the  next  section  of  the  tank.  (Cf.  U.  S.  Patent  1,247,540. 
Ref.  No.  341.) 


'  **i  r  'T&e-  Actiwatttd  Sludge  Process 


4  Work  of  the  Lawrence  Experiment  Station  for  1913— The  Purification  of 
sewage  and  water  and  investigations  on  allied  subjects.     H.  W.   CLARK 

and  S.  DE  M.  GAGE.  45th  Annual  Report  State  Board  of  Health  of  Mass.  265- 
368.  Respecting  the  aeration  of  sewage,  the  studies  begun  in  1912  were  con- 
tinued with  various  modifications  and  a  new  aerating  tank  put  into  operation 
on  Jan.  2nd.  Aerating  periods  varying  from  24  to  5  hours,  and  air  volumes 
ranging  from  200,000  to  25,000  cu.  ft.  per  hour  per  million  gallons  of  sewage 
were  tried,  the  results  of  the  various  changes  in  the  methods  of  operating 
producing  far  less  differences  in  the  efficiency  of  the  process  than  might  be 
expected.  The  effect  of  the  gelatinous  growths  in  reducing  the  Kjeldahl  N  was 
clearly  established,  as  was  also  the  clarifying  effect  of  aerating  with  sludge. 
Effluent  stability  was  more  pronounced  when  the  sewage  was  aerated  10 
hours  or  more.  A  brief  historical  review  of  sewage  aeration  work  is  given, 
as  well  as  several  tables  of  analytical  data. 

1914 

5  Purification  of  sewage  or  other  impure  waters.     W.  JONES  and  JONES  & 
ATTWOOD,  LT'D.,   Stourbridge,   Eng.     British  Patent  729,   Jan.   10,  1914. 

Jour.  Soc.  Chem.  Ind.  34,  197.  Chem.  Abst.  9,  1814.  The  sewage  is  purified  in 
presence  of  air  and  cultivated  sludge  in  an  annular  tank.  Transverse  depres- 
sions are  formed  in  the  floor  of  the  tank  at  intervals  and  in  each  depression  a 
plate  is  suspended  so  that  the  circulating  sewage  has  to  pass  underneath  the 
plate  in  each  depression.  Circulation  is  brought  about  by  admitting  com- 
pressed air  at  the  bottom  of  each  depression  in  such  a  way  as  to  mix  with  the 
sewage  on  one  side  of  the  plate  only.  The  upper  part  of  the  plate  is  so  formed 
as  to  deflect  the  rising  current  horizontally  towards  the  next  depression. 

6  Sewage  treatment  by  aeration  and  contact  in  tanks  containing  layers  of 
slate.     H.  W.  CLARK  and  G.  O.  ADAMS.     Eng.  Record  69,  158-9.     Chem. 

Abst.  8,  1319.  Sewage  treated  with  air  in  tanks  with  vertical  slate  walls  one 
inch  apart,  gave  87%  removal  of  suspended  matter  with  5  hours  aeration. 

7  Experimental  plant  for  treating  sewage  at  Brooklyn,  N.  Y.     G.  T.  HAM- 
MOND.   Munic.  Jour.  36,  233-9.    Munic.  Eng'rg.  47,  427-36.    Equipment  in- 
cludes various  tanks  and  apparatus  for  the  investigation  of  sewage  treatment 
by  forced  aeration.     Plant  not  operating  long  enough  to  justify  publishing 
results. 

8  The   present   position    of   the   sewage   disposal    problem.      G.    J.   FOWLER. 

Surveyor  45,  504-6.  Engineer  117,  272.  Wasser  u.  Abwasser  8,  417-8. 
Trans.  Liverpool  Engr.  Soc.  35,  213-23.  Sanit.  Record  53,  294.  Expt.  Sta. 
Record  32,  88.  The  sanitary  aspects  of  sewage  disposal  are  discussed  with 
reference  to  conditions  permitting  use  of  the  sludge  as  fertilizer.  The  author 
anticipates  the  time  when  it  will  be  possible  to  purify  sewage  completely  in  a 
tank,  with  production  of  inoffensive  sludge  which  can  be  disposed  of  as  fer- 
tilizer. The  forced  aeration  experiments  at  Lawrence,  Mass.,  and  those  in 
progress  at  Davyhulme  (Manchester,  Eng.)  are  referred  to. 

9  Experiments   on  the  oxidation  of   sewage  without   the  aid   of   niters,   I. 

E.  ARDERN  and  W.  T.  LOCKETT.  Jour.  Soc.  Chem.  Ind.  33,  523-39.  Sur- 
veyor 45,  610.  Chem.  Abst.  8,  2207.  Expt.  Sta.  Record  32,  387.  The  solid 
matter  obtained  by  prolonged  aeration  of  sewage — which  for  reference  pur- 
poses and  the  want  of  a  better  name  has  been  designated  "activated  sludge" — 
has  the  power  of  enormously  increasing  the  purification  of  sewage  by  simple 
aeration,  its  effect  depending  upon  intimate  contact  with,  and  its  proportion  in 
the  raw  sewage.  Unoxidized  solids  should  not  be  allowed  to  accumulate.  Tem- 
perature exerts  considerable  influence.  Laboratory  experiments  indicate  that 
purification  of  average  strength  Manchester  sewage  can  be  accomplished  in 
6  to  9  hours,  using  25%  sludge.  DR.  J.  GROSSMANN,  F.  R.  O'SHAUGHNESSY,  S. 
E.  MELLING,  P.  GAUNT,  J.  T.  THOMPSON  and  DR.  G.  J.  FOWLER  participated 
in  the  discussion,  covering  mainly  the  composition  of  the  sludge,  operating 

8 


Abstract  Bibliography — 1914 

costs  and  possible  revenues  from  the  process.  Several  tables  of  analytical 
data  are  given. 

10  Apparatus   for    the    purification   of   sewage   and    analagous    liquids.     W. 

JONES  and  JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Worcestershire,  Eng. 
British  Patent  19,915,  April  11,  1914.  Jour.  Soc.  Chem.  Ind.  33,  1170.  Chem. 
Abst.  10,  655.  A  pipe,  reaching  nearly  to  the  bottom  of  a  tank  containing 
the  sewage,  extends  over  a  partition  to  the  bottom  of  a  second  tank;  com- 
pressed air  is  delivered  into  the  end  of  the  pipe  in  the  first  tank,  thus  causing 
a  mixture  of  liquid  and  air  to  pass  over  into  the  second  tank;  the  lower  end 
of  the  pipe  in  this  tank  has  a  perforated  chamber  which  distributes  the  air 
into  the  liqud.  A  supplementary  volume  of  air  is  introduced  into  the  descend- 
ing pipe  in  the  second  tank. 

11  Apparatus    for   the   purification   of   sewage    and    analogous    liquids.     W. 

JONES  and  JONES  &  ATTWOOD,  LT'D.,  Stourbridge,  Eng.  British  Patent 
19,916,  April  11,  1914.  Jour.  Soc.  Chem.  Ind.  34,  632.  Chem.  Abst.  10,  655. 
In  an  aerating  tank  for  the  treatment  of  sewage,  the  floor  of  the  tank  is 
divided  into  a  number  of  saucer-like  depressions,  in  the  center  of  which  is  a 
porous  plate.  Compressed  air  is  admitted  to  chambers  below  the  porous  plates, 
and  fine  bubbles  rise  from  their  upper  surface;  currents  of  liquid  upwards 
over  the  porous  plates  and  downwards  between  the  depressions  are  thus 
produced,  carrying  with  them  the  suspended  solids  and  bacteria.  The  bottom 
of  the  tank  being  curved  or  inclined  downwards  to  the  diifusers  from  points 
between  the  same,  cause  the  deposited  solids  falling  to  the  bottom  of  the  tank 
between  the  diffusers  to  pass  under  the  influence  of  the  air  currents  from  the 
latter.  The  sewage  is  admitted  at  the  bottom  of  one  end  of  the  tank  and  flows 
over  a  wall  at  the  other  end.  After  aeration  is  completed,  the  liquid  is  allowed 
to  stand  till  clear,  when  the  clarified  liquid  is  run  off  and  the  solids  allowed  to 
remain.  Fresh  sewage  is  then  admitted  at  once  and  the  aeration  recommenced. 
fCf.  U.  S.  Patent  1,282,587,  Ref.  No.  428.) 

12  Sewage   purification  by   aeration:     Manchester   experiments.     EDITORIAL. 
Surveyor  46,  113-4.    Experimental  results  promising.    Costs  still  in  doubt. 

Tank  capacity  should  be  1.5  times  dry  weather  flow,  based  on  12  hour  period. 
Preliminary  calculations,  from  meager  data,  give  approximately  1  cu.  ft.  of 
air  per  gallon  of  sewage.  Cautions  with  regard  to  cost  of  such  large  volumes 
of  air. 

13  Apparatus  for  purifying  sewage.     G.  W.  &  J.  F.  NAYLOR,  Denby  Dale, 
Yorks,  Eng.     British  Patent  20,259,  Sept.  28,  1914.    Jour.  Soc.  Chem.  Ind. 

34,  814.  Chem.  Abst.  10,  655.  A  tank  has  a  false  bottom  of  porous  tiles,  so 
supported  that  the  air  space  below  each  row  of  tiles  is  separate  from  the 
adjoining  air  space.  Air  under  pressure  is  admitted  through  horizontal  pipes 
laid  below  each  row  of  tiles.  The  tiles  may  be  supported  directly  on  the  floor 
of  the  tank  or  may  fit  in  trays.  The  air  pipes  may  support  the  trays  or 
the  tiles,  or  may  have  short  upright  branches  supporting  them.  The  pipes 
and  branches  have  perforations  for  the  passage  of  the  air  to  the  under  side 
of  the  tiles. 

14  Apparatus  for  purifying  sewage.     G.  W.  &  J.  F.  NAYLOR,  Denby  Dale, 
Yorks,  Eng.     British  Patent  20,579,  Oct.  6,  1914.     Jour.  Soc.  Chem.  Ind. 

34,  978.  Chem.  Abst.  10,  945.  In  the  purification  of  sewage  by  aeration  in 
a  tank  with  a  false  bottom  of  porous  material,  the  false  bottom  is  made  of 
a  pliable  material,  such  as  filter-cloth,  felt,  canvas,  or  perforated  metal, 
supported  if  desired  on  wire  netting,  through  which  the  air  supply  diffuses 
into  the  sewage  in  the  tank.  The  porous  floor  may  be  laid  on  the  air 
pipes  placed  horizontally  along  the  bottom  of  the  tank,  or  on  the  framework 
covering  each  line  of  pipes  and  dividing  the  air  space  into  separate  compart- 
ments. The  floor  may  also  be  supported  on  boxes  with  porous  sides,  the  air 
pipes  coming  through  the  bottom  of  the  tank  and  being  in  a  vertical  position 
in  the  center  of  each  box. 

9 


The  Activated  Sludge  Process 

15  Purification  of  sewage  and  analogous  liquids.  W.  JONES  and  JONES  & 
ATTWOOD,  LT'D.,  Stourbridge,  Eng.  British  Patent  21,976,  Nov.  4,  1914. 
Jour.  Soc.  Chem.  Ind.  35,  272.  Chem.  Abst.  10,  1068.  Active  bacterial  sludge 
is  prepared  by  forcing  air  in  small  bubbles  through  raw  sewage,  keeping  the 
latter  in  circulation.  After  a  time  the  sludge  is  allowed  to  deposit,  the  liquid 
run  off,  a  fresh  quantity  of  sewage  run  in,  and  the  process  repeated.  Sufficient 
active  sludge  is  prepared  to  fill  the  treatment  tank  one-fifth  to  one-third  full. 
The  tank  is  then  filled  up  with  raw  sewage.  The  tank  is  formed  of  one  or 
more  long  endless  channels  of  rectangular  form,  the  bottom  of  the  tank  sloping 
to  one  end.  The  dividing  wall  between  the  two  portions  of  the  channel  has 
vertical  slits  in  it  so  as  to  permit  the  free  passage  of  sludge  and  water  and 
the  maintenance  of  level  throughout  the  channel.  Air  is  supplied  in  small 
bubbles  transversely  across  the  channel  at  several  points,  and  just  in  front 
of  these  points  a  baffle  plate  is  hung.  In  this  way  the  rising  mixture  of  air 
and  sewage  causes  a  current  of  sewage  under  the  baffle,  and  the  current  is 
kept  up  throughout  the  channel,  inducing  a  continuous  circulation  of  the 
sewage.  Aeration  is  conducted  for  one  to  five  hours  and  then  stopped  for 
one  or  two  hours,  the  clear  liquid  then  drawn  off  down  to  as  low  a  level 
as  desired,  and  the  tank  then  filled  up  with  fresh  sewage.  The  sludge  formed 
from  each  charge  is  drawn  off  from  time  to  time.  Closed  tanks  may  also  be 
used,  the  air  liberated  at  the  surface  of  the  first  channel  being  led  to  the  bot- 
tom of  the  adjoining  one  and  so  on,  the  last  channel  being  open  or  the  air  led 
away  by  a  shaft.  The  pressure  of  the  air  over  the  liquid  may  also  be  used 
for  emptying  the  channels.  When  the  sewage  is  below  46°  F.  (8°  C.)  it  is 
warmed  to  this  temperature  in  order  that  nitrification  of  the  sludge  may 
not  be  hindered.  Aerating  sewage  in  the  presence  of  humus  obtained  from  fil- 
ter beds  is  also  claimed.  The  aeration  is  carried  out  by  forcing  air  through 
porous  bodies,  such  as  porous  earthenware,  textile  fabrics,  cocoanut  fiber  or 
lead  wool.  A  suitable  apparatus  is  shown. 

16  Means  of  and  methods  for  treating  sewage.    W.  M.  BECKETT,  Manchester, 
Eng.    British  Patent  21,985,  Nov.  4,  1914.    Jour.  Soc.  Chem.  Ind.  34,  1269. 

Chem.  Abst.  10,  1068.  The  sewage  enters  a  closed  tank  having  a  floor  pervious 
to  air.  Compressed  air  rising  through  the  floor  agitates  and  aerates  the  sew- 
age and  sludge,  and  the  gases  given  off  are  passed  with  the  air  to  a  destructor 
or  other  combustion  furnace.  The  purified  liquid  is  discharged  from  the  tank 
by  a  floating  arm,  down  to  a  certain  level,  below  which  the  sludge  is  allowed 
to  collect,  a  portion  being  run  out  from  time  to  time.  Porous  tiles,  perforated 
pipes,  etc.,  may  be  used  for  the  pervious  floor. 

17  Purification  of  sewage  and  analogous  liquids.     W.   JONES  and  JONES  & 
ATTWOOD,  LT'D.,  Stourbridge,  Eng.     British  Patent  22,736,  Nov.  19,  1914. 

Jour.  Soc.  Chem.  Ind.  35,  195.  Chem.  Abst.  10,  1241.  Sewage  is  admitted 
gradually  to  a  tank  containing  a  residuum  of  activated  sludge  from  a  pre- 
ceding operation,  and  air  is  blown  through  it  from  the  bottom  of  the  tank 
at  the  same  time,  the  operation  taking  one  to  six  hours.  When  the  tank  is 
full  aeration  is  stopped,  the  sewage  allowed  to  remain  quiescent  for  one  or 
two  hours,  the  clear  liquid  being  then  drawn  off  from  the  top  down  to  the 
level  of  the  sludge  layer  in  about  half  an  hour.  If  through  any  cause  the 
sludge  should  get  less  active,  it  may  be  drawn  off  into  side  tanks  for  aeration, 
and  afterwards  returned  to  the  main  tank.  Cultures  of  organisms  may  be 
added  to  the  tank  to  assist  in  the  purification  process.  Several  tanks  ma} 
be  worked  in  combination,  in  which  case  the  valves  for  supplying  air  and 
sewage  and  for  discharging  the  liquid  are  operated  in  sequence  by  automatic 
means,  such  as  float  valves,  or  a  water-clock,  or  other  time-piece  operating 
pneumatic  or  electrical  devices,  so  that  the  operation  is  continuous.  (Cf. 
U.  S.  Patent  1,247,543,  Ref.  No.  344.) 

18  Purification  of  sewage  and  analogous  liquids.     W.  JONES  and  JONES  & 
ATTWOOD,  LT'D.,  Stourbridge,  Eng.     British  Patent  22,737,  Nov.  19,  1914. 

Jour.  Soc.  Chem.  Ind.  35,  195.     Chem.  Abst.  10,  1241.     A  tank  of  continuous 

10 


Abstract  Bibliography — 1914 

channel  form  with  semi-circular  ends  is  used,  the  space  enclosed  by  the  inner 
wall  of  the  channel  forming  an  inner  tank.  Air  diffusers  are  placed  along 
the  bottom  of  the  tank,  and  just  behind  these,  baffle  plates  are  let  down  from 
the  surface.  The  mixture  of  sewage  and  air  passes  under  the  bottom  and 
rises  up  the  side  of  the  baffle,  and  thus  produces  a  forward  movement  of  the 
sewage  along  the  tank.  A  weir  leads  from  one  part  of  the  channel  into 
the  inner  tank,  and  some  distance  in  front  of  this  weir  the  introduction  of 
air  is  stopped,  so  that  there  is  time  for  some  sedimentation  of  the  sludge  to 
take  place  before  the  sewage  passes  into  the  inner  tank,  which  constitutes  a 
settling  tank  and  from  the  upper  part  of  which  the  purified  sewage  is  con- 
tinuously drawn  off.  The  sludge  deposited  in  the  inner  tank  is  lifted  back 
by  an  air-lift  into  the  treatment  tank.  An  annular  treatment  tank  or  one 
in  the  form  of  a  zig-zag  channel  may  also  be  used.  (Cf.  U.  S.  Patent  1,247,542, 
Ref.  No.  343.) 

19  The  complete  bacterial  treatment  of  sewage  without  filters.    W.  NAYLOR. 
Surveyor  46,  592-4.     Chem.  Abst.  9,  229.     In  discussion  of  the  paper  by 

ARDERN  and  LOCKETT,  (Ref.  No.  9),  mention  is  made  of  isolated  instances 
of  purification  without  filters  on  sewage  farms  where  the  sewage  was  al- 
lowed to  stand  in  pools.  This  purification  required  considerable  time.  It  is 
noted  that  one  volume  of  sludge  to  4  or  5  of  sewage  used  in  the  experiments 
of  A.  and  L.  is  almost  too  solid  to  deal  with,  as  ordinary  precipitation  methods 
give  one  part  of  sludge  to  110  of  sewage  and  require  6  hours  for  settling. 
The  air  used  for  aerating  may  require  after-treatment  on  account  of  odors 
taken  up  from  the  sewage.  Sludge  disposal  should  be  made  easier  because 
the  material  is  non-putr^scezit  and  it  should  be  pressed  more  easily,  as  it 
would  be  leas  slimy  than  ordinary  sludge. 

20  Tank  for  the  purification  of  sewage.    G.  W.  &  J.  F.  NAYLOR,  Denby  Dale, 
Yorks,  Eng.    British  Patent  23,146,  Nov.  27,  1914.    Jour.  Soc.  Chem  .Ind. 

34,  1269.  Chem.  Abst.  10,  1389.  The  tank  has  a  level  floor  and  is  divided 
into  several  compartments  by  baffle  plates  reaching  from  the  top  nearly  to 
the  bottom,  and  which  may  be  inclined  in  the  direction  of  the  flow  of  sewage. 
Porous  tiles  are  fitted  in  the  floor  behind  each  baffle  plate  and  air  is  forced 
through  the  tiles.  Air  may  also  be  blown  over  the  surface  of  the  sewage  by 
pipes  attached  to  the  top  of  the  baffle  plates.  The  circulation  of  the  sewage 
is  assisted  by  the  upward  current  of  air  and  the  sludge  is  kept  in  suspension. 
The  exit  pipe  of  the  tank  is  provided  with  a  float  discharge,  arranged  to 
empty  three-fourths  of  the  contents,  leaving  the  remainder  to  activate  the 
succeeding  supply  of  sewage.  The  baffle  plates  may  also  be  arranged  to 
reach  the  bottom  of  the  tank,  and  pipes  provided  passing  through  each  plate. 
The  tank  may  be  divided  longitudinally  into  two  sections  to  economize  space. 

21  Sewage  treatment  by  aeration.    EDITORIAL.    Surveyor  46,  674.     Comment 
on  paper  by  W.  H.  DUCKWORTH.     (Ref.  No.  22).     Caution  recommended 

with  regard  to  cost  data. 

22  Aeration  experiments  with  activated  sludge.     W.  H.  DUCKWORTH.     Sur- 
veyor 46,  681-2.    Chem.  Abst.  9,  679.     Experiments  at  the  Salford  sewage 

works  showed  successful  treatment  of  sewage  by  the  process  of  ARDERN  and 
LOCKETT.  In  tanks  of  34,500  gallons  capacity  with  25%  sludge,  75,000  gallons 
could  be  treated  in  21  hours.  One  hour  to  fill,  3  hours  of  aerating,  2  hours  to 
settle  and  one  hour  to  empty;  7  hours  for  complete  treatment  of  one  tankfull. 
Purification  was  90%  on  the  oxygen  absorption  and  76%  on  the  albuminoid 
ammonia.  The  sludge  contained  only  half  the  fat  of  ordinary  sewage  sludge, 
while  the  phosphoric  acid  was  twice  and  the  nitrogen  about  3  times  the 
amount  in  ordinary  sludge.  As  the  experiments  were  made  with  apparatus 
at  hand,  and  in  connection  with  the  regular  work  of  the  plant,  no  accurate 
cost  figures  could  be  given. 

23  Oxidation  of  sewage  without  the  aid  of  filters,  II.     E.  ARDERN  and  W.  T. 
LOCKETT.     Jour.  Soc.  Chem.  Ind.  33,  1122-4.     Chem.  Abst.  9,  679.  Expt. 

11 


The  Activated  Sludge  Process 

Sta.  Record  34,  888.  Continuous  flow  experiments  with  a  tank  of  35  gallons 
capacity  were  satisfactory  though  the  tank  was  not  designed  for  best  results. 
Perforated  pipes  distributed  the  air.  Sludge  was  re-aerated.  Fill  and  draw 
experiments  in  50  gallon  casks,  using  porous  tiles  for  air  diffusers  also  gave 
satisfactory  results,  4  hours  aeration  with  25%  sludge  showing  a  purification 


by 

perforated  pipes.  Comparative  results  are  given  in  tabular  form.  Experi- 
ence shows  the  necessity  for  adequate  scientific  control.  Experiments  using 
a  tank  of  20,000  gallons  capacity,  400  sq.  ft.  area,  are  being  made.  This 
should  handle  60,000  gallons  of  sewage  daily. 

24  The   purification   of   Salford   sewage  along   the  lines   of   the   Manchester 
experiments.     S.  E.  MELLING.     Jour.  Soc.  Chem.  Ind.  33,  1124-30.     Chem. 

Abst.  9,  679.  Refers  to  the  same  work  as  described  under  reference  22.  It 
is  an  established  fact  that  it  is  possible  to  clarify  and  purify  crude  sewage 
in  bulk  in  3  hours,  the  effluent  produced  satisfying  any  local  or  international 
standard.  Several  tables  of  analytical  data  accompany  the  article.  In  the 
discussion,  MR.  J.  P.  WAKEFORD  referred  to  the  promising  tests  of  the  acti- 
vated sludge  process  at  Wakefield,  Eng.,  (Cf.  Ref.  No.  63),  where  various 
trade  wastes  were  encountered.  The  dry  sludge  there  contained  43.99% 
organic  matter,  56.01%  mineral  water;  total  N,  4.59%,  phosphates,  2.74%, 
iron,  9.67%.  The  possibility  of  the  iron  acting:  as  a  catalyst  in  flocculating 
the  colloids  was  suggested.  MR.  W.  H.  DUCKWORTH  stated  that  80,000 
gallons  per  day  were  being  treated  at  Salford  on  the  fill  and  draw  plan.  A 
12,000  gallon  continuous  flow  tank  is  contemplated.  Some  difficulty  had  been 
experienced  through  the  stopping  up  of  the  holes  in  the  perforated  pipes.  DR. 
G.  J.  FOWLER  said  that  the  idea  which  started  these  particular  researches 
really  originated  at  Lawrence,  Mass.  In  his  opinion,  the  iron  bacterium 
"M7"  probably  played  some  part  in  the  process.  MR.  J.  H.  LESTER,  MR.  W. 
THOMPSON,  DR.  J.  GROSSMANN  and  DR.  E.  ARDERN  also  participated  in  the 
discussion,  the  latter  emphasizing  the  importance  of  complete  admixture  and 
intimate  contact  of  the  activated  sludge  with  the  sewage,  describing  as  use- 
ful for  this  purpose,  a  specially  prepared  porous  tile  air  diffuser. 

25  Sewage  treatment  by  aeration.     EDITORIAL.     Surveyor  46,  701.     Analogy 
drawn  between  the  Lawrence,  Mass,  slate  tank  experiments  and  ARDERN 

and  LOCKETT'S  experiments.  Filters  become  choked  and  the  amount  of  air 
supplied  cannot  be  controlled  as  in  the  activated  sludge  process.  Cost  data 
again  asked  for. 

26  A  recent  development  of  the  sewage  problem.    E.  ARDERN.    Surveyor  46, 
714-7.    Sanitary  Record  54,  401,  413;  55,  5-6.    Chem.  Abst.  9,  679.  A  report 

of  the  bottle  and  cask  experiments  at  Davyhulme,  Manchester,  (Ref.  No.  9) 
and  a  summary  of  the  Salford  work.  (Ref.  Nos.  22,  24.)  Grit  should  be  re- 
moved. Proportions  of  sludge  to  sewage  should  be  1  to  4.  Purification  is  seri- 
ously diminished  below  10  C.,  and  trade  wastes  may  have  inhibitory  action. 
Costs  discussed  briefly. 

27  Purification  of  sewage.    G.  W.  &  J.  F.  NAYLOR.    Denby  Dale,  Yorks,  Eng. 
British   Patent  24,386,   Dec.   21,   1914.     Jour.   Soc.   Chem.   Ind.   35,    195. 

Chem.  Abst.  10,  1567.  A  tank  is  divided  into  compartments  by  vertical  baffles 
and  is  provided  with  an  air  supply  from  tubes  entering  the  pipes  by  which  the 
sewage  flowing  over  the  baffles  is  led  to  the  lower  portion  of  the  next  compart- 
ment. In  an  alternative  form,  air  is  supplied  to  rows  of  boxes  with  perforated 
or  permeable  faces  fixed  to  one  or  each  side  of  the  baffles;  the  boxes  may  be 
arranged  checker- wise,  with  the  permeable  faces  delivering  horizontally;  or 
obliquely  overlapping,  with  inclined  permeable  faces  alternately  directed  up- 
wards and  downwards.  Agitators  may  be  used  to  mix  the  sludge  at  the  bottom 
of  the  tank  with  the  incoming  sewage,  and  may  also  deliver  air  into  the  sewage. 

12 


Abstract  Bibliography — 1915 

28  Apparatus    for   the   purification   of    sewage   and   analogous    liquids.     W. 

JONES  and  JONES  &  ATTWOOD,  LT'D.,  Stourbridge,  Eng.  British  Patent 
24,630,  Dec.  24,  1914.  Jour.  Soc.  Chem.  Ind.  35,  195.  Chem.  Abst.  10,  1686. 
A  tank  has  a  discharge  pipe  practically  flush  with  the  bottom,  and  over  the  pipe, 
and  fitting  on  it,  is  a  superposed  series  of  rings  or  cylinders  reaching  above 
the  surface  of  the  liquid  in  the  tank,  all  the  joints  being  water-tight.  When 
all  the  rings  are  in  position  the  series  forms  a  closed  tube.  Each  ring  is  con- 
nected with  the  one  below  it  by  sliding  links  which  permit  of  the  rings  being 
lifted  in  succession  from  the  top  and  which  leave  a  considerable  space  between 
the  lifted  ring  and  the  one  below  it.  As  each  ring  is  lifted,  liquid  flows  into 
the  mouth  of  the  next  lower  ring,  and  in  this  way  the  tank  is  emptied  in  suc- 
cessive layers  from  the  surface.  The  rings  are  lifted  by  means  of  a  pulley  chain 
connected  with  a  bucket  which  is  filled  from  a  cistern  through  a  regulated  tap, 
the  cistern  being  filled  with  liquid  from  the  tank  by  a  pipe  near  the  surface  with 
a  regulating  tap.  When  all  the  rings  have  been  lifted  a  percussion  valve  in  the 
bottom  of  the  pulley  bucket  is  opened  automatically  and  the  bucket  emptied; 
the  empty  bucket  being  raised  again  by  the  rings  in  the  tank  subsiding  into 
their  places.  In  an  alternative  form  of  the  apparatus,  part  of  the  discharge 
end  of  the  tank  is  formed  of  wooden  slats  working  in  grooves,  the  top  slat  being 
connected  at  each  end  to  a  pair  of  pulley  chains  and  lifting  those  below  it  by 
links,  the  discharge  in  this  case  taking  place  through  the  end  of  the  tank.  The 
pulley  bucket  works  inside  of  the  tank.  Another  method  of  effecting  the  dis- 
charge is  by  a  float  carrying  a  siphon  discharge  pipe  which  empties  into  the 
tank  discharge  pipe,  the  float  being  counterbalanced  by  a  weight  acting  over  a 
pulley.  The  short  legs  of  the  siphon  are  trapped  by  cups  just  below  the  surface 
of  the  liquid.  Sludge  is  discharged  from  the  tank  when  desired,  by  valves  in 
the  bottom.  The  discharge  apparatus  may  be  arranged  to  open  and  close  the 
sewage  inlet  valves  of  the  tank  and  to  actuate  the  air  supply  valve. 

29  A  recent  development  of  the  sewage  problem.    DISCUSSION.     Surveyor  46, 
754.    In  the  discussion  of  the  paper  by  E.  ARDERN  (Ref.  No.  26),  DR.  G.  J. 

FOWLER  describes  how  previous  work  led  up  to  activated  sludge  experiments. 
W.  H.  DUCKWORTH  discusses  the  Salford  work.  DR.  ARDERN  claims  the  sludge 
is  granular  and  can  be  handled  easily  by  simple  straining  filters.  Hopes  that 
the  length  of  the  accumulation  period  may  be  cut  down. 

30  Experiments  upon  the  purification  of  sewage  and  water  at  the  Lawrence 
experiment  station  during  the  year  1914.    H.  W.  CLARK  and  G.  O.  ADAMS. 

46th  Annual  Report  Mass.  State  Dept.  Health.  295-346.  Chem.  Abst.  11, 
177.  Expt.  Sta.  Record  35,  887.  In  the  chapter  on  the  purification  of  sewage 
by  aeration  and  growths,  (pp  301-9)  are  reports  on  the  aerating  tank  put 
into  operation  in  January,  1913,  and  of  three  others  which  were  started  to 
determine  the  effect  of  this  treatment  on  raw,  settled,  and  septic  sewage. 
The  effect  of  aeration  in  a  secondary  tank  was  also  studied.  Calculated  on 
capacity,  all  of  these  tanks  contained  5  to  15%  of  slate.  Air  was  supplied 
through  jets  in  the  tank  bottom,  with  deflecting  baffles  to  cause  circulation 
of  the  sewage.  With  a  5  hour  aeration  period,  and  air  supplied  at  the  rate 
of  25,000  and  50,000  cu.  ft.  per  hour  per  million  gallons  of  sewage,  all  the 
effluents  were  well  clarified  and  20  to  50%  of  the  samples  taken  were  stable. 
5  hours  re-aeration  increased  the  proportion  to  90%.  Tabulated  analytical 
data  showing  free  and  albuminoid  ammonia,  organic  and  inorganic  N,  O  con- 
sumed, and  bacterial  removal  are  given. 

1915 

31  Sewage  treatment  by  aeration.    G.  B.  KERSHAW.     Surveyor  47,  8.     The 
treatment  of  storm  water,  up  to  three  times  the  dry  weather  flow,  will 

be  expensive.  Refers  to  the  Brooklyn  aeration  experiments  where  the  cost 
of  air  was  considered  high  with  2  hours  aeration. 

32  Sanitary  engineering  in   1914.       The  activated  sludge  system.       ANON. 
Engineer   119,   32.     A  brief  outline  of  the   activated   sludge   process   is 

13 


The  Activated  Sludge  Process 

given,  with  particular  reference  to  the  production  of  the  active  sludge.  The 
bearing  of  the  organism  "M7"  on  the  process  is  considered,  as  are  the  experi- 
ments of  DR.  FOWLER,  ARDERN  &  LOCKETT,  W.  H.  DUCKWORTH,  S.  E.  MELLING, 
and  J.  P.  WAKEFORD. 

33  Purification  of  sewage  and  other  liquids.   W.  JONES  and  JONES  &  ATTWOOD, 
LT'D.,  Stourbridge,  Eng.     British  Patent  1,141,  Jan.  23,  1915.     Jour.  Soc. 

Chem.  Ind.  35,  326.  Chem.  Abst.  10,  2017.  Air  is  supplied  to  the  sewage  mixed 
with  the  sludge,  not  uniformly  as  is  usual,  but  intermittently,  or  in  varying 
volumes  or  at  varying  pressures,  or  both,  during  the  period  of  aeration.  By 
employing  a  relatively  small  volume  of  air  over  a  long  period,  the  aeration 
of  the  sewage  may  be  effected,  and  by  increasing  the  volume  or  pressure  for  a 
short  period,  the  sludge  and  sewage  are  thoroughly  mixed.  In  this  way  a 
smaller  quantity  of  air  is  used  than  for  a  uniform  supply.  An  automatic 
valvular  apparatus  is  provided  which  consists  of  a  bucket-wheel  in  a  tank 
of  water,  to  which  compressed  air  is  supplied,  causing  the  wheel  to  rotate. 
The  spindle  of  the  wheel  carries  a  cam  which  operates  a  valve  in  piston  form 
in  connection  with  an  air  chest;  when  the  piston  is  raised  air  passes  from 
the  chest  to  a  pipe  leading  to  a  main  air  valve  which  it  actuates.  The  valve 
passes  compressed  air  either  directly  to  the  diffusing  pipes  in  the  sewage 
tank,  in  which  case  a  pulsating  effect  is  produced  in  the  sewage,  or  first  to 
an  air  receiver  which  after  being  filled  is  allowed  to  empty  into  the  dif- 
fusing pipes,  in  which  case  a  gradually  decreasng  volume  of  air  is  supplied 
to  the  sewage.  Other  methods  of  varying  the  air  supply  are  also  described. 
(Cf.  U.  S.  Patent  1,247,541,  Ref.  No.  342  and  Can,  Patent  183,586,  Ref.  No.  402.) 

34  Apparatus  for  introducing  gases  into  intimate  contact  with  liquid  sewage. 
G.  W.  MOTTRAM,  Deepcar,  Yorks,  Eng.     British  Patent  2,421,  Feb.   16, 

1915.  Jour.  Soc.  Chem.  Ind.  35,  434.  In  a  vertical  cylindrical  sewage  tank, 
the  apparatus  takes  the  form  of  a  vertical  rotating  shaft  carrying  a  pair  of 
arms  at  its  lower  end.  The  shaft  is  hollow  and  compressed  air  is  supplied 
through  it  to  the  arms,  which  are  made  of  perforated  pipes  or  of  plain  metal 
pipes  carrying  earthenware  pipes.  These  earthenware  pipes  are  arranged 
concentrically  around  the  metal  pipes  and  spaced  from  them  by  distance 
pieces  to  provide  an  air  passage.  The  earthenware  pipe  is  porous  prefer- 
ably along  one  section  of  its  length  only.  In  a  rectangular  tank  the  air 
diffusing  pipes  are  supported  at  each  end  on  wheels  running  along  rails 
on  the  bottom  of  the  tank,  or  are  suspended  from  arms  supported  on  wheels 
on  rails  on  the  top  of  the  walls  of  the  tank.  The  air  supply  is  brought  by 
flexible  piping  to  one  of  the  supporting  arms  which  takes  it  to  the  air  diffusing 
pipes.  (Cf.  U.  S.  Patent  1,195,067,  Ref.  No.  177.) 

35  Observations   on   some   European   water   purification   plants   and   sewage 
disposal  works.     E.   BARTOW.     Jour.  Am.   Waterworks  Assoc.  2,  213-24. 

Chem.  Abst.  9,  1521.  Univ.  III.  Bull.  13,  162-72.  (Water  Survey  Series  No. 
12,  1915.)  Reference  is  made  to  the  experiments  on  the  aeration  of  sewage 
in  the  presence  of  activated  sludge  in  progress  at  Manchester,  Eng.,  and  to 
similar  work  which  is  being  carried  on  by  the  Water  Survey  Station  at  the 
Univ.  of  111.  at  Urbana. 

36  English  experiments  on  sewage  aeration  revived  as  preliminary  to  the 
Baltimore  tests.     L.  C.  FRANK.     Eng.  Record  71,  288-9.     Chem.  Abst.  9, 

1645.  Enumerates  some  features  of  the  activated  sludge  process  at  Manches- 
ter and  Salford  as  described  by  ARDERN  and  LOCKETT,  and  others.  (Ref.  Nos. 

9,  22,  23,  24.)      A   continuous   flow  tank   will   supercede   the   fill   and   draw 
methods. 

37  Treatment  of  sewage.     C.  H.  COOPER,  Wimbleton,  Surrey,  Eng.     British 
Patent  3,831,  March  10,  1915.    Jour.  Soc.  Chem.  Ind.  35,  326.    Chem.  Abst. 

10,  2116.     A  portion  of  sewage  which  has  been  activated  is  mixed  with  raw 
sewage  in  an  enlargement  of  the  mouth  of  a  vertical  pipe  up  which  the  raw 

14 


DIVERSITY  OF  CALIFORNIA    ^ 

=  NT   OF  CIVIL  ENGINEERING 


Abstract  Bibliography — 1915 

sewage  is  conveyed  .  The  mixture  passes  out  through  a  nozzle  in  the  side  of 
the  enlargement  and  below  the  surface  of  the  sewage;  at  the  same  time  com- 
pressed air  is  blown  through  the  nozzle  with  the  sewage  mixture.  In  this  way 
the  sewage  mixture  is  atomized  as  it  leaves  the  nozzle,  and  afterwards  is 
mixed  further  with  air  drawn  in  through  louvres  against  the  lower  sides  of 
which  the  atomized  sewage  impinges. 

38  The   purification   of  sewage   by   aeration.   R.   O.   WYNNE-ROBERTS.     Can. 
Engr.  28,  335-6.     Contract  Record  29,  647-9.     Chem.  Abst.  9,  1210.       The 

aeration  of  sewage  is  reviewed,  particularly  the  work  of  CLARK  and  GAGE  at 
Lawrence,  Mass.,  and  that  of  FOWLER  and  MUMFORD,  in  which  the  iron  bac- 
terium played  a  part.  The  activated  sludge  work  of  ARDERN  and  LOCKETT  at 
the  Davyhulme  works,  Manchester,  Eng.,  DR.  E.  BARTOW  at  Urbana,  DUCK- 
WORTH and  MELLING  at  Salford,  and  of  J.  P.  WAKEFORD  at  Wakefield  are  also 
noted  and  some  of  their  results  given,  including  cost  estimates.  The  proposed 
activated  sludge  experiments  at  Milwaukee,  Baltimore  and  Regina,  Sask., 
Canada,  the  latter  in  some  detail,  are  also  referred  to. 

39  Apparatus  for  introducing  gases  into  intimate  contact  with  liquids.     G. 

W.  MOTTRAM,  Sheffield,  Eng.  British  Patent  4,240,  March  18,  1915.  Jour. 
Soc.  Chem.  Ind.  35,  521.  The  gas  is  passed  into  a  pipe  of  porous  material  or 
a  conduit  formed  of  porous  tiles  or  blocks  immersed  in  the  liquid.  The  porous 
tubes,  tiles  or  blocks  are  formed  of  coarse  materials,  and  are  provided  with 
a  surface  facing  of  much  finer  material,  so  that  while  the  gas  passes  easily 
through  the  coarser  layers,  it  is  very  finely  divided  by  the  finer  material 
before  it  comes  in  contact  with  the  liquid. 

40  Sewage  aeration  at  Lawrence  and  Manchester  compared.     H.  W.  CLARK. 
Eng.  Record  71,  367-8.     Chem.  Abst.  9,  1521.     Mr.  Clark  states  that  the 

heavy,  brownish  gray,  gelatinous  and  other  growths  upon  the  slate  beds  at 
Lawrence  which  clarify  the  circulating  sewage  are  probably  the  same  bodies 
as  those  developed  by  FOWLER  and  ARDERN  &  LOCKETT  in  the  Manchester 
tank  and  called  "activated  sludge." 

41  Can  sewage  sludge  be  made  valuable  as  a  fertilizer?     EDITORIAL.     Eng. 
News  73,  593.     Expt.  Sta.  Record  33,  423.     Refers  to  a  paper  presented 

by  DR.  E.  BARTOW  and  to  a  sample  of  dried  activated  sludge  exhibited  by  him 
at  the  meeting  of  the  Lake  Mich.  Water  Com.  held  at  Milwaukee  on  March 
19,  1915.  Sample  contained  6%  N  in  a  form  available  for  plant  food,  and  the 
estimated  value  of  the  sludge  in  N,  P,  and  K  compounds  was  $15  to  $20 
per  ton. 

42  Sewage  aeration  experiments  in  the  United  States.     EDITORIAL.    Surveyor 
47,  449.     Refers  to  the  continuous  flow  activated  sludge  experiments  to 

be  started  by  the  U.  S.  Public  Health  Service  at  Baltimore,  Md.,  using  a 
modified  Imhoff  tank. 

43  Purification  of  sewage  by  aeration  in  the  presence  of  activated  sludge. 
E.  BARTOW  and  F.  W.  MOHLMAN.     Jour.  Ind.  Eng.  Chem.  7,  318-20.    Eng. 

News  73,  647-8.  Eng.  Record  71,  421-2.  Eng.  &  Contg.  43,  310-1.  Munic. 
Jour.  38,  504-5.  Jour.  Soc.  Chem.  Ind.  34,  508.  Surveyor  47,  642.  Chem.  Abst. 
9,  1521.  Expt.  Sta.  Record  33,  423,  786;  38,  490.  Univ.  III.  Bull.  14,  325-35. 
(Water  Survey  Series  No.  13.)  Experiments  at  Urbana,  111.,  with  fresh 
sewage  of  domestic  origin,  showed  that  nitrate  was  formed  in  15  days  by 
blowing  4830  cu.  ft.  of  air.  By  siphoning  off  the  supernatant  liquid  and  re- 
filling, sludge  was  accumulated.  On  the  31st  treatment  3  cu.  ft.  of  air  per 
gallon  of  sewage  was  required  in  5  hours.  Nitrification  was  complete.  One 
hour  aeration  seemed  practically  sufficient.  Worm  life  was  active.  (Aeolosoma 
hemprichi).  The  sludge  contained  on  a  dry  basis,  6.3%  N,  4.0%  fat,  1.44% 
phosphoric  acid  and  75%  volatile  matter. 


UNIVERSITY  OF  CALIFORNIA 

DEPARTMENT  OF  CIVIL  ENGINEERING 


The  Activated  Sludge  Process 

44  The  Milwaukee,  Wis.,  sewage  tests.     NEWS  ITEM.     Eng.  News.  73,  650. 
Briefly  reviews  the  methods  tried  and  states  that  "large  scale  studies  of 

activated  sludge  are  to  be  made  under  the  direction  of  DR.  GILBERT  J.  FOWLER 
of  Manchester,  Eng." 

45  An   exceptionally    promising    method    of   sewage    treatment.      EDITORIAL. 
Eng.  &  Contg.  43,  306.     Commenting  on  the  work  of  BARTOW  and  MOHL- 

MAN,  (Ref.  No.  43),  it  is  noted  that  their  activated  sludge  experiments  indi- 
cate a  stable  effluent,  a  commercially  valuable  residual  sludge,  and  that  the 
process  is  free  from  nuisance.  The  cost  question  is  of  chief  consideration, 
though  the  effects  of  low  temperatures,  amount  of  air  necessary,  and  flexi- 
bility of  the  process  are  points  yet  to  be  tleared  up. 

46  Activated  sludge  in  sewage  oxidation.     EDITORIAL.     Munic.  Jour.  38,  509. 
Refers  to  English  experiments;  discusses  the  question  of  practicability;  the 

possible  necessity  of  keeping  the  air  at  certain  temperatures;  and  expresses 
the  hope  that  some  way  may  be  found  to  operate  continuous  flow  tanks  rather 
than  the  intermittent  type. 

47  Co-operation  sought  in  conducting  activated  sludge  experiments  at  Balti- 
more.— L.  C.  FRANK  and  C.  W,  HENDRICK.    Eng.  Record  71,  521-2.    Chem. 

Abst.  9,  1521.  Discussion  of  design  and  operation  of  continuous  flow  aero  tanks 
is  accompanied  by  request  for  suggestions  and  criticisms. 

48  Process  of   purifying  sewage  or  other  wastes,   and   apparatus   therefor. 
L.  C.  FRANK,  Washington,  D.  C.  U.  S.  Patent  1,139,024,  May  11,  1915. 

(Application  filed  April  2,  1915.  10  claims.)  Off.  Gaz.  214,  498.  Jour.  Soc. 
Chem.  Ind.  34,  680.  Chem.  Abst.  9,  1647.  Purifying  sewage  by  agitating  and 
oxidizing  a  flowing  stream  at  one  point  in  its  path  by  injection  of  jets  of  air, 
allowing  the  sediment  to  settle  at  another  point  in  the  path  of  flow,  and  return- 
ing the  sediment  to  the  point  of  oxidation  for  further  treatment.  The  sewage 
is  led  down  by  a  pipe  to  the  bottom  of  a  central  chamber  of  the  tank  and  flows 
upwards.  Air  is  admitted,  also,  at  the  bottom,  and  oxidizes  the  sewage  which 
overflows  at  the  top  of  the  chamber  into  two  V-shaped  side  chambers  where 
settling  takes  place;  the  deposited  solids  fall  through  openings  at  the  bottom 
of  the  side  chambers  into  the  central  chamber,  while  the  clear  liquid  passes  to 
the  effluent  channel.  (This  patent  dedicated  to  the  public.) 

49  Aeration  method  of  purifying  sewage.    J.  P.  WAKEFORD.    Inst.  Munic.  and 
County  Engrs.    June,  1915.    Can.  Engr.  29,  249-51.    Chem.  Abst.  9,  2785. 

Experiments  on  activated  sludge  are  described.  Barrel  and  bottle  tests  showed 
complete  oxidation  of  the  ammonia  by  aeration  for  two  hours.  A  porous  tile 
diffuser  was  used.  In  a  large  tank  holding  11,000  gallons  exclusive  of  25% 
sludge,  operated  on  the  fill  and  draw  plan,  a  cycle  of  half -hour  fill,  two  hours 
blow,  two  hours  settlement  and  half-hour  empty,  worked  well.  90  cu.  ft.  of 
air  per  minute  was  used  under  a  pressure  of  5  Ibs.  per  sq.  in.  The  sludge  con- 
tained 4.59%  nitrogen.  Analyses  of  sludge  and  sewage  are  given. 

50  Activated  sludge  experiments  at  Baltimore.    L.  C.  FRANK  and  C.  W.  HEN- 
DRICK.    Surveyor  47,  693.     Chem.  Abst.  9,  2786.     Continuous  flow  neces- 
sary for  economical  operation.     Oxidation  promoted  by  fineness  of  bubbles. 
Aeration  may  be  effected  by  (a)  impact  of  inflowing  sewage,  (b)  aeration,  (c) 
mechanical  devices.     Sludge  must  be  returned  from  settling  to  aeration  tank. 

51  Fertilizers.     G.  J.  FOWLER  and  G.  MUMFORD.     British  Patent  8,397,  June 
7,  1915.     Jour.  Soc.  Chem.  Ind.  35,  1074.     Chem.  Abst.  10,  2948.     A  fer- 
tilizer is  produced  by  sterilizing  any  form  of  sewage  sludge  by  heat  and  re- 
storing bacterial  activity  by  the  addition  of  fresh  active  residue  or  sludge 
produced  by  the  aeration  of  sewage  or  like  liqiud  in  the  presence  of  bacteria. 
The  temperature  of  sterilization  is  preferably  not  higher  than  the  boiling 
point  of  water,  and  the  proportion  of  the  active  sludge  added  is  from  5  to  10% 

16 


Abstract  Bibliography — 1915 

of  the  bulk.  In  a  modification,  the  fertilizer  is  produced  by  a  partial  steriliza- 
tion of  the  active  residue  or  sludge  at  a  temperature  of  about  60°  or  70°  C. 
(Cf.  Danish  Patent  22,389,  Ref.  No.  309:  U.  S.  Patent  1,294,080,  Ref.  No.  454: 
Can.  Patent  189,921,  Ref.  No.  467.) 

52  Treatment  of  sewage  sludge.    ANON.     Trans.  Can.  Soc.  C.  E.  28,   part  2. 
Can.  Engr.  28,  697-9.     A  discussion  of  P.   GILLESPIE'S  paper  by  R.  O. 

WYNNE-ROBERTS  in  which  the  activated  sludge  experiments  of  DR.  FOWLER 
and  ARDERN  &  LOCKETT  at  Manchester,  Eng.,  and  of  W.  H.  DUCKWORTH  at 
Salford  are  briefly  described. 

53  Activated  sludge  and  the  Baltimore  experiments.    W.  S.  COULTER.     Eng. 
Record  71,  784.    In  a  letter  to  the  editor  a  continuous  flow  activated  sludge 

tank  is  suggested,  which  comprises  an  aerating  and  settling  tank,  the  latter 
having  a  hopper  bottom  with  very  steep  sides,  communicating  through  a  bottom 
outlet  with  a  chamber  from  which  the  deposited  sludge  can  be  raised  and  de- 
livered as  desired  by  an  air  lift. 

54  Activated  sludge  experiments  in  Canada.     R.  O.  WYNNE-ROBERTS.     Can. 
Engr.  29,  112.    Munic.  Eng'rg.  49,  68-9.    Surveyor  48,  211.    Chem.  Abst.  9, 

2787.  Refers  to  experiments  at  Regina,  Can.,  in  which  two  galvamzed-iron 
tanks  4  ft.  7.5  in.  diam.,  by  24  ft.  deep,  with  glass  windows  in  the  side  were 
used.  About  577  gallons  of  sewage  was  treated  in  each  tank,  that  in  tank  one 
by  straight  blowing,  perforated  pipes  distributing  the  air,  while  in  the  other 
tank  aeration  was  produced  by  injecting  air  by  means  of  a  centrifugal  pump. 
The  air  was  intended  to  be  supplied  at  the  rate  of  15  cu.  ft.  per  sq.  ft.  of  tank 
area  per  hour,  but  was  not  closely  controlled  in  the  second  tank.  Absence  of 
objectionable  odors  were  noted,  but  no  results  or  conclusions  are  given. 

55  Activated  sludge  and  the  Baltimore  sewage  experiments.    G.  J.  REQUARDT. 
Eng.  Record.  72,  23.     In  a  letter  to  the  editor  Mr.  Requardt  refers  to  the 

use  of  converted  Imhoff  tanks  for  activated  sludge  experiments  and  suggests 
that  better  oxidation  may  be  obtained  by  having  the  flow  perpendicular  to  the 
direction  of  the  agitating  air  bubbles.  Sketch  of  a  suggested  horizontal  con- 
tinuous flow  tank  is  also  included. 

56  Tanks  for  the  purification  of  sewage.     G.  W.  &  J.  F.  NAYLOR.     British 
Patent  9,870,  July  7,  1915.    Jour.  Soc.  Chem.  Ind.  35,  615.     In  tanks  for 

the  purification  of  sewage  wherein  air  is  forced  through  porous  tiles,  the  latter 
are  arranged  at  the  bottom  of  the  tank  in  continuous  rows,  curves  or  circles, 
in  such  a  manner  as  to  enclose  areas  which  are  available  for  the  deposition  of 
the  sludge. 

57  Purification  of  sewage.    G.  W.  &  J.  F.  NAYLOR.    Denby  Dale,  Yorks,  Eng. 
British  Patent  9,989,  July  9,  1915.    Jour.  Soc.  Chem.  Ind.  35,  434.    A  tank 

is  used  with  a  porous  floor  under  which  pipes  are  laid  for  diffusing  air  through 
the  floor  to  aerate  the  sewage.  The  floor  of  the  tank  is  divided  into  sections, 
either  zones,  quadrants,  parallel  strips  or  squares.  The  pipes  under  the  floor  are 
placed  parallel  or  crossing  each  other,  and  have  alternate  perforated  and  blank 
lengths,  so  as  to  supply  air  to  alternate  sections  of  the  floor.  The  air  is  sup- 
plied under  a  low  pressure  through  valves  controlled  by  a  clockwork  arrange- 
ment which  is  worked  so  as  to  supply  air  to  the  various  sections  alternately  or 
in  any  desired  combination. 

58  Activated  sludge  experiments  at  Milwaukee,  Wis.     T.  C.  HATTON.     Eng. 
News,  74,  134-7.    Surveyor  48,  258-61.     Chem  Abst.  9,  2412.     Tests  of  the 

activated  sludge  method  of  sewage  treatment  are  described.  A  large  fill  and 
draw  tank,  a  continuous  flow  tank  of  the  same  size,  and  two  small  tanks  pro- 
vided with  glass  windows  are  included  in  the  studies  being  made.  Methods  of 
air  diffusion,  volume  and  time  of  air  application,  and  cost  records  are  given. 

17 


The  Activated  Sludge  Process 

59  The  sludge  problem:  standards  for  effluents  recommended  by  the  Royal 
Commission  on  Sewage  Disposal,  and  sewage  purification  by  aeration  in 

the  presence  of  activated  sludge.  H.  M.  WILSON.  Surveyor  48,  74-6.  Chem. 
Abst.  10,  793.  A  short  account  of  the  development  of  the  activated  sludge 
method  and  the  results  of  its  use  leads  to  the  conclusion  that  the  process  pro- 
duces satisfactory  purification,  but  the  cost  of  operation  has  not  yet  been  fully 
worked  out. 

60  Activated   sludge   in  America.     W.   N.   BAKER.     Eng.  News   74,   164-71. 
Chem.  Abst.  9,  2412.    Exp.  Sta.  Record  34,  332.    Notes  on  the  new  process 

of  sewage  treatment  gathered  by  Mr.  Baker  on  visits  to  several  experimental 
plants.  Sewage  is  aerated  in  the  presence  of  an  accumulation  of  aerated  sludge. 
There  is  reason  to  hope  that  a  high  degree  of  clarification — and  perhaps  bac- 
terial reduction  when  necessary — with  a  stable  effluent  and  a  quick  drying 
sludge,  high  in  fertilizing  value,  can  be  produced  by  this  process. 

61  Brooklyn  sewage  aeration  and  activated  sludge  experiments.     E.  J.  FORT. 
Eng.  News  74,  214-7.     Chem.  Abst.  9,  2682.     Studies  have  been  made  of 

sewage  aeration  by  compressed  air  passed  upwards  from  a  pipe  grid  and  shal- 
low gravel  bed  through  sewage  passing  downwards,  in  a  deep  tank  containing 
9  horizontal  disk  deflectors.  The  first  experiments  with  plain  aeration  of  the 
sewage  in  this  tank  were  not  very  encouraging,  an  air  supply  of  0.75  volume 
per  volume  of  sewage  with  two  hours  retention,  being  insufficient  to  produce 
any  marked  improvement  on  crude  sewage.  The  second  experiment  was  carried 
out  in  an  aerated  contact  bed.  The  improvement  was  very  marked,  the  24  hour 
samples  being  almost  of  drinking  water  quality.  The  third  experiment  dealt 
with  the  activated  sludge  process  and  was  carried  out  in  the  same  tank  as  the 
first  experiment.  The  continuous  flow  and  fill  and  draw  plan  was  tried  alter- 
natively. 24  hours  aeration  resulted  in  100%  relative  stability. 

62  Sewage  purification  by  forced  aeration.     EDITORIAL.     Surveyor  48,   129. 
Comment  on  paper  by  J.  P.  WAKEFORD.     (Ref.  No.  63.)     High  moisture 

content  of  sludge  is  undesirable.  Odors  and  costs  questioned.  Careful  control 
necessary.  J.  D.  WATSON'S  caution  against  trade  wastes  cited,  also  E.  B. 
MARTIN'S  remark  that  he  was  unable  to  find  a  satisfactory  air  diffuser  at  Sal- 
ford. 

63  Brief  notes  of  experiments  in  sewage  purification  by  forced  aeration.    J.  P. 

WAKEFORD;  Surveyor  48,  132-3.  Can.  Engr.  29,  429.  Chem.  Abst.  10,  793. 
Expt.  Sta.  Record  34,  488.  At  Wakefield,  Eng.,  experiments  were  carried  out 
in  a  tank  30  by  12  by  6.5  ft.  on  the  fill  and  draw  plan,  allowing  0.5  hour  for 
filling,  2  hours  for  blowing,  2  hours  for  settling  and  0.5  hour  for  emptying. 
Results  were  satisfactory,  but  several  engineering  difficulties  must  be  overcome 
before  the  process  can  be  worked  on  a  large  scale.  When  this  is  done  it  is 
safe  to  assume  that  the  treatment  will  be  less  offensive,  more  rapid,  will  require 
less  area,  and  be  less  expensive  to  maintain  than  present  processes,  on  account 
of  the  omission  of  chemicals,  greater  fertilizing  value  of  the  sludge,  and  less 
expense  for  attendance. 

64  The  activated  sludge  process.    EDITORIAL.    Can.  Engr.  29,  239.    Refers  to 
articles  by  ARDERN  &  LOCKETT,  (Ref.  Nos.  9  and  23),  and  by  S.  E.  MEL- 
LING  (Ref.  No.  24)  on  the  Manchester  and  Salford  work,  and  notes  that  ex- 
periments are  under  way  in  several  places  in  the  United  States  and  Canada, 
with  concordant  results  in  general  considering  the  variety  of  the  experiments. 
The  Canadian  authorities  can  be  depended  upon  to  take  an  important  part  in 
these  investigations.     The  principles  of  the  process  are  discussed. 

65  Experiments  in  sewage  purification  by  forced  aeration.   DISCUSSION.    Sur- 
veyor 48,  143-6.     Discussion  of  J.  P.  WAKEFORD'S  paper.     (Ref.  No.  63.) 

Large  tank  volumes  considered  necessary.    J.  D.  WATSON  criticises  complexity 

18 


Abstract  Bibliography — 1915 

of  the  process  and  is  sceptical  regarding  its  practicability.  E.  B.  MARTIN 
discusses  undesirability  of  tarry  matters  in  sewage  and  the  difficulties  in 
handling  variations  in  flow.  A.  T.  GOOSEMAN,  R.  BROWN,  E.  H.  CRUMP,  C.  H. 
COOPER  and  E.  J.  SILCOCK  also  participated  in  the  discussion. 

66  Activated  sludge  sewage  treatment.     EDITORIAL.     Munic.  Jour.  39,  257. 
Refers  to  the  several  experimental  plants  in  the  United  States  and  to  the 

encouraging  results  obtained.  Discusses  the  plant  at  Milwaukee  and  concludes 
that  the  process  promises  extremely  well,  though  many  practical  points  are  yet 
to  be  studied. 

67  Experiments  on  separate  digestion  of   activated  sludge  needed.     W.  L. 

STEVENSON.  Eng.  Record  72,  238.  In  a  letter  to  the  editor,  the  author 
suggests  the  desirability  of  experimentation  on  the  separate  digestion  of  acti- 
vated sludge  in  order  to  obtain  a  sludge  of  less  bulk,  and  freedom  from  odor. 

68  Sewage  disposal  by  aeration.    EDITORIAL.    Surveyor  48,  253.     The  results 
of  experiments  on  sewage  aeration  are  inconclusive  as  yet.     The  most 

difficult  questions  to  be  settled  are,  the  best  method  of  air  diffusion  and  the 
adoption  of  the  process  to  the  continuous  method  of  treatment.  Varying  the 
depth  of  the  tanks,  or  properly  baffling  the  tank  to  obtain  maximum  contact 
with  the  air,  may  be  a  solution  of  the  first  question. 

69  Activated  sludge  progress  at  Cleveland.     R.  W.  PRATT.     Eng.  News  74, 
571.    Chem.  Abst.  9,  2957.    A  unit  to  handle  one  million  gallons  of  sewage 

is  to  be  built.  The  experimental  tank  gave  good  results  with  3  hours  aeration 
and  10  to  15  minutes'  sedimentation. 

70  Milwaukee's  activated  sludge  plant;  the  pioneer  large-scale  installation. 

T.  C.  HATTON.  Eng.  News  74,  667-8.  Eng.  Record  72,  481-4.  Surveyor  48, 
564-7.  Engineer  121,  58-9.  Chem.  Abst.  10,  77.  The  plant  consists  of  11  cir- 
cular reinforced  concrete  tanks,  30  ft.  inside  diam.  by  13  ft.  max.  depth.  Tanks 
1  to  8  inclusive  are  the  aerating  tanks  in  which  the  sewage  mixed  with  acti- 
vated sludge  is  aerated.  Tank  9  is  used  as  the  sedimentation  tank  and  tanks 
10  and  11  are  the  activated  sludge  tanks.  Drawings  are  given  showing  the 
curved  baffles  and  the  manner  of  sloping  the  bottom  of  the  running-through 
channels  of  the  aerating  tanks.  The  sewage  enters  tank  1  and  is  aerated  with 
the  sludge,  then  passes  to  tank  2  and  is  again  aerated,  and  so  on  through  the 
other  tanks  to  tank  9,  where  it  is  settled.  The  sludge  from  this  tank  is  dis- 
charged by  gravity  into  tanks  10  and  11,  where  it  is  aerated  to  maintain  the 
nitrogen  cycle.  From  these  tanks  the  sludge  is  pumped  to  the  inlet  chamber 
of  tank  1.  Activated  sludge  which  is  in  excess  of  that  needed  is  dried  and  used 
for  fertilizer.  The  plant  is  designed  to  treat  1,600,000  gallons  of  sewage  per 
day  with  a  four-hour  period  of  aeration  and  with  25%  activated  sludge.  It  is 
estimated  that  the  cost  will  be  $5.30  per  million  gallons,  exclusive  of  engine 
room  and  plant  labor,  and  the  cost  of  disposal  of  the  sludge. 

71  Oxidation  of  sewage  without  the  aid  of  niters,  III.    E.  ARDERN  and  W.  T. 
LOCKETT.    Jour.  Soc.  Chem.  Ind.  34,  937-43.    Surveyor  48,  450-4.     Chem. 

Abst.  10,  502,  794.  Expt.  Sta.  Record  34,  888.  Manchester  sewage  was  aerated 
in  50-gal.  casks,  but  not  to  complete  nitrification.  In  4  weeks  enough  sludge 
was  obtained  to  give  satisfactory  results  with  8  hours  aeration.  Data  as  to 
amount  of  sludge  produced  were  not  conclusive.  Mineral  precipitates  were 
added  to  the  sludge,  but  no  advantage  ensued ;  a  deflocculating  action  was  fre- 
quently observed.  Experiments  in  gallon  bottles  indicate  that  the  volume  of 
air  necessary  may  be  as  low  as  6  cu.  ft.  per  hour  per  sq.  ft.  of  tank  area.  The 
best  proportion  of  sludge  to  sewage  is  given  as  2:3  for  Manchester  sewage. 
Estimated  cost  of  air  per  million  gal.  of  sewage:  Min.  $1.98,  Max.  $4.92,  with 
electricity  at  one  cent  per  kw.  hour. 

19 


The  Activated  Sludge  Process 

72  American  Sewerage  Practice.    METCALF  &  EDDY.     (Book)     Vol.  Ill,  First 
Edition,  1915.     pp.  222,  386-94.     A  brief  general  review  of  the  activated 

sludge  process  is  given,  with  mention  of  the  work  done  at  Lawrence,  Milwaukee, 
111.  State  Water  Survey  at  Urbana,  and  Manchester,  Eng. 

73  Activated  sludge  progress  at  Houston,  Texas.     ANON.     Eng.  News  74, 
717.    Can.  Engr.  29,  503.    Chem  Abst.  10,  240.     In  a  communication  from 

the  city  engineer,  Mr.  E.  E.  SANDS,  statement  is  made  that  a  14,000  gallon 
tank  has  just  begun  operating  and  is  expected  to  be  running  normal  in  a  few 
weeks.  The  small  12  in.  square,  8  ft.  deep  tank  is  also  operating. 

74  Purification  of  sewage  by  the  utilization  of  activated  sludge.     E.  LONG, 
Manchester,  Eng.    British  Patent  14,733,  Oct.  19,  1915.    Jour.  Soc.  Chem. 

Ind.  35,  1129.  Chem.  Abst.  11,  1229.  Screened  sewage  is  passed  downward 
through  a  pipe  containing  a  form  of  injector  nozzle,  and  means  are  provided 
for  admitting  air  to  this  part  of  the  pipe,  or  compressed  air  may  be  introduced. 
The  mixture  of  sewage  and  air  passes  into  a  widened  portion  of  the  pipe 
which  contains  a  rotary  agitator,  and  thence  through  a  rotary  pump  into  the 
bottom  of  a  tank.  A  pipe  connects  the  top  of  the  tank  with  the  pipe  above 
the  injector  nozzle,  and  the  apparatus  may  be  worked  so  as  to  circulate  the 
contents  of  the  tank  until  a  sludge  is  obtained  so  altered  in  character  as  to 
justify  the  term  "activated  sludge."  The  apparatus  may  also  be  employed  for 
circulating  a  mixture  of  activated  sludge  and  sewage  or  waste  water. 

75  The  world's  first  full-scale   plant  for  the  treatment  of  sewage   by   the 
activated  sludge  process.    T.  C.  HATTON.    Eng.  &  Contg.  44,  322-7.    Can. 

Engr.  29,  517-9,  549-50.  Proc.  Am.  Soc.  Munic.  Improv.  22,  (1915).  Engineer 
121,  58-9.  Chem.  Abst.  10,  78.  Tests  on  the  plant  at  Milwaukee  are  described, 
showing  bacteria  removals  of  99%  and  cost  data  indicating  a  partial  cost  of 
$4.43  per  million  gallons  of  sewage  when  1.77  cu.  ft.  of  air  per  gallon  are 
used.  A  stable  effluent  is  produced  with  city  sewage  containing  250  p.p.m.  of 
suspended  matter.  The  sludge  contained  5.45%  of  ammonia. 

76  Has  the  activated  sludge  process  of  sewage  treatment  made  good?     EDI- 
TORIAL.   Eng.  &  Contg.  44,  322.    Commenting  on  the  work  at  Milwaukee, 

it  is  noted  that  the  activated  sludge  process  is  exceedingly  flexible,  free  from 
nuisance,  and  provides  a  high  degree  of  bacterial  removal  and  clarification. 
Winter  conditions  of  operating  are  yet  to  be  studied. 

77  Sewage  treatment  by  aeration.    EDITORIAL.    Surveyor  48,  445.    Continuous 
flow  desirable.    Air  costs  not  so  great  as  thought  at  first.    Investigation 

of  effect  of  tanks  of  various  depths  is  urged. 

78  Choosing  air  compressors  for  activated  sludge  tanks.     C.  H.   NORDELL. 
Eng.  News  74,  904-6.    Chem.  Abst.  10,  238.     Reciprocating  and  hydraulic 

air  compressors,  turbo-blowers,  and  positive  pressure  blowers  are  discussed. 
Positive  pressure  blowers  are  useful  in  small  installations  while  turbo-blowers 
are  best  for  large  plants. 

79  Sewage  treatment  and  the  war.     EDITORIAL.    Eng.  News  74,  899.     Com- 
ments on  the  passing  of  the  Royal  Commission  on  Sewage  Disposal  and 

the  improbability  of  Imhoff  tank  installations  in  England  for  some  time,  sug- 
gesting that  when  the  war  is  over  there  may  be  some  surprising  realignment 
of  sewage  treatment  and  that  the  activated  sludge  process,  if  its  possibilities 
and  economies  are  then  shown,  may  find  its  way  to  all  parts  of  the  world. 

80  British  Engineer  submits  an  activated  sludge  query.     O.  J.  WILKINSON. 
Eng.  News  74,  948.    Chem.  Abst.  10,  238.    Attention  is  called  to  the  simi- 
larity of  sprinkling  filters  and  activated  sludge,  in  that  both  depend  upon  the 
passage  of  sewage  in  thin  films  over  active  sludge.     Grit  should  be  removed. 
Uniform  contact  and  distribution  are  requisite.     The  cost  is  not  yet  definitely 
known. 

20 


Abstract  Bibliography — 1915 

81  Activated  sludge  at  Milwaukee,  Wis.    ANON.    Munic.  Jour.  39,  776.    Re- 
cent information  concerning  tests  being  made.    Effect  of  low  temperatures. 

Plant  for  continuous  operation.    Results  and  cost  of  treatment. 

;    I   :  • 

82  Activated  sludge  and  the  Baltimore  sewage  experiments.    O.  J.  WILKINSON. 
Eng.  Record  72,  640.    In  a  letter  to  the  editor  Mr.  Wilkinson  refers  to  his 

experience  with  the  activated  sludge  process  and  to  proposals  for  tanks  of  vari- 
ous designs,  the  general  difficulty  being  to  keep  the  particles  of  activated  sludge 
uniformly  distributed  and  at  the  same  time  in  intimate  contact  with  the  whole 
of  the  flow,  without  excessive  use  of  air. 

83  Recent  results  of  experiments  on  the  purification  of  sewage  by  aeration 
in  the  presence  of  activated  sludge,  at  the  University  of  Illinois.       E. 

BARTOW  and  F.  W.  MOHLMAN.  Eng.  &  Contg.  44,  433-4.  Eng.  News  74,  1096-7, 
Jour.  Ind.  Eng.  Chem.  8,  15.  Jour.  Soc.  Chem.  Ind.  35,  555.  Chem.  Abst. 
10,  362.  Expt.  Sta.  Record  34,  591.  Univ.  III.  Bull.  14,  325-35.  (Water  Sur- 
vey Series  No.  13.)  A  test  plant  of  4  tanks,  each  3  ft.  2  in.  square  by  8  ft.  5 
in.  deep,  has  been  operated  on  domestic  sewage  on  the  fill  and  draw  plan.  The 
sludge  was  accumulated  on  a  6-hour  cycle.  Results  show  that  one  sq.  ft.  of 
filtros  in  10  sq.  ft.  tank  area  is  not  sufficient,  but  that  3  in  10  gives  the  best 
results.  About  one  cu.  ft.  of  air  per  gallon  of  sewage  was  used,  though  more 
was  required  for  strong  sewage.  The  free  ammonia  and  presence  of  nitrates 
was  used  as  indicators. 

84  The  fertilizer  value  of  activated  sludge.    E.  BARTOW  AND  W.  D.  HATFIELD. 
Eng.  &  Contg.  44,  434-6.    Jour.  Ind.  Eng.  Chem.  8,  17-20.    Jour.  Soc.  Chem. 

Ind.  35,  552.  Am.  City  14,  282-5.  Chem.  Abst.  10,  365.  Pot  studies  and  gar- 
dening experiments  show  that  the  N  in  activated  sludge  is  in  a  very  avail- 
able form  and  that  this  sludge  is  a  valuable  fertilizer,  being  comparable  with 
dried  blood.  (Cf.  Ref.  No's.  118  and  444.) 

85  The  treatment  of  sewage  by  aeration  in  the  presence  of  activated  sludge. 

E.  BARTOW.  Metal.  &  Chem.  Eng'rg.  13,  901-4.  Trans.  Am.  Inst.  Chem. 
Eng.  8,  119-29:  (1915).  Chem.  Abst.  10,  794.  Expt.  Sta.  Record  34,  591;  37, 
87.  Status  of  the  activated  sludge  process  of  sewage  treatment  in  America, 
with  details  of  the  work  done  at  the  State  Water  Survey  station,  Univ.  of 
Illinois,  Urbana,  111.  (Cf.  Ref.  No.  83.) 

86  Activated   sludge   plants   for   packinghouse   wastes.     NEWS   ITEM.     Eng. 
News,  74,  1101.     Experimental  activated  sludge  plants  are  being  built  in 

Chicago  by  SULZBERGER  &  SONS  Co.  and  by  ARMOUR  &  Co.  It  is  stated  that 
at  a  recent  conference  of  engineers  and  chemists  representing  the  Chicago 
packinghouse  interests,  much  enthusiasm  was  shown  for  the  activated  sludge 
process,  and  that  some  even  went  so  far  as  to  declare  that  it  was  the  only 
process  of  sewage  treatment  brought  to  their  attention  which  gives  promise 
of  satisfactorily  treating  the  liquid  wastes  from  the  packinghouses,  and  at 
the  same  time  recovering  the  valuable  material  which  they  contain. 

87  Sewage  disposal  by  aeration.     EDITORIAL.     Surveyor  48,  562.     Comment 
on  the  Milwaukee  experiments.     (Ref.  No.  70.)     Questions  if  tanks  are 

deep  enough.     Cost  data  very  interesting. 

88  A  year  of  activated  sludge.     W.  T.  CARPENTER.     Annual  Report  N.  J. 
Sanit.  Assoc.     (1915).    Following  a  brief  historical  review  of  the  process, 

the  Brooklyn  experiments  on  the  fill  and  draw  plan  are  described.  For  this 
work  a  16,000  gallon  tank  was  used,  perforated  pipes  diffusing  the  air  at 
the  rate  of  about  1.17  volumes  per  volume  of  sewage  per  hour.  The  experi- 
ments on  the  continuous  flow  plan  utilized  a  tank  of  4  ft.  diam.  by  8  ft.  deep 
of  about  900  gallons  capacity,  the  air  being  diffused  through  carborundum 
discs.  Both  experiments  were  promising  from  a  chemical  and  bacteriological 
standpoint.  The  work  of  DR.  BARTOW  at  Urbana,  111.,  and  of  MR.  T.  C. 

21 


The  Activated  Sludge  Process 

HATTON  at  Milwaukee  is  referred  to,  the  advantages  and  disadvantages  of 
the  process  being  summed  up  in  closing. 

89  A  year  of  activated  sludge  at  Milwaukee,  Wis.     G.  W.  FULLER.     Eng. 
News  74,  1146-7.    Surveyor  49,  233-4.     Chem.  Abst.  10,  239.     The  author 

accepts  the  theory  of  activated  sludge  as  correct  but  comments  on  practice. 
At  Milwaukee  2  to  3  hours  aeration  removes  96  to  99%  of  the  bacteria  and 
nitrifies  the  effluent  according  to  the  amount  of  air  used.  Odors  are  removed ; 
the  sludge  dries  readily;  though  the  process  may  fail  through  excessive  or 
insufficient  aeration  or  the  presence  of  mineral  grit. 

90  Activated  sludge  treatment  for  packinghouse  wastes.    NEWS  ITEM.     Eng. 
News  74,  1148.    Chem.  Abst.  10,  238.    At  the  Chicago  stockyards  ARMOUR 

&  Co.  after  successful  experiments  with  small  tanks,  now  have  an  experi- 
mental plant  with  a  tank  of  20,000  gallons  capacity  working  on  the  continuous 
flow  plan  with  excellent  results  since  early  in  Nov.  1915.  MORRIS  &  Co.  and 
SWIFT  &  Co.  have  plants  of  the  same  general  character,  and  the  latter  is 
said  to  be  building  a  500,000  gallon  plant.  SULZBERGER  &  SONS  Co.  are  re- 
ported to  be  experimenting  with  both  the  activated  sludge  and  the  electroly- 
tic processes.  The  above  are  independent  but  relate  to  the  investigations 
carried  on  by  the  Sanitary  District  of  Chicago  respecting  the  utility  of  the 
activated  sludge  process  for  treating  the  trade  wastes  from  the  stockyards. 
The  latter  is  building  a  plant  to  handle  150,000  gallons  of  sewage  daily. 

91  Activated  sludge  system  of  sewage  purification.    G.  J.  FOWLER.    Surveyor 
48,  604.    In  a  letter  to  the  editor  DR.  FOWLER  reports  that  JONES  &  ATT- 

WOOD  have  installed  a  fill  and  draw  plant  at  the  Baguley  Sanatorium  of  the 
Manchester  Corporation,  and  that  they  have  also  started  continuous  flow  ex- 
periments at  Stamford  and  Worcester  (Eng.)  The  latter  plant  is  to  treat 
2  million  g.  p.  d.  The  first  tank  used  at  Milwaukee  was  designed  by  J.  &  A., 
who  claim  all  patent  rights. 

92  Method  of  and  apparatus  for  the  treatment  and  purification  of  sewage. 

E.  B.  MARTIN,  Eccles,  Lancastershire,  Eng.  British  Patent  17,463,  Dec. 
14,  1915.  Jour.  Soc.  Chem.  Ind.  36,  160.  The  apparatus  consists  of  a  cylin- 
drical tank  divided  into  segments,  each  segment  forming  a  treatment  unit. 
The  apparatus  may  be  worked  on  the  continuous  flow  or  the  quiescent  system, 
or  on  a  combination  of  both.  The  sewage  enters  any  one  segment  where  it 
meets  with  activated  sludge,  and  the  mixture  is  agitated  by  air  blown  in 
from  the  bottom  and  evenly  distributed  by  baffle  plates.  The  treated  sewage 
overflows  into  a  radial  trough  in  which  any  sludge  settles  put  and  which  is 
run  back  into  the  segment,  while  the  liquid  flows  over  a  weir  and  is  led  into 
to  the  next  segment  for  further  treatment.  One  or  more  of  the  last  segments 
is  used  for  a  settling  tank  before  the  completely  purified  liquid  is  discharged. 
One  segment  is  always  being  emptied  and  cleaned  in  the  cycle  of  working. 
The  activated  sludge  is  run  out  from  each  segment  into  a  central  well.  The 
volume  of  air  supplied  to  any  segment  can  be  varied  at  will  by  adjustable 
valves. 

93  The  activated  sludge  experiments  at  Salford,  Eng.    W.  H.  DUCKWORTH. 
Biggs  &  Sons'  Contractors  Record  15.      (Dec.  15,  1915).     Surveyor  48, 

648-52.  Engineer  120,  620-1.  Munic.  Jour.  40,  199-200.  Chem.  Abst.  10,  1064. 
Continuation  of  the  Salford  experiments  (Ref.  No.  24)  has  given  satisfactory 
purification  of  sewage  with  2  hours  blowing  of  air,  even  in  winter,  and  part 
of  the  time  with  only  one  hour  aeration.  The  presence  of  trade  wastes  of  a 
sterilizing  nature  at  times  necessitates  longer  periods  of  blowing  to  restore 
the  activity  of  the  sludge.  Success,  with  some  of  the  air  jets  clogged  up,  leads 
to  the  conclusion  that  a  smaller  amount  of  air  might  be  used.  In  continuous 
treatment  60,000  gallons  per  day  are  treated  in  an  aeration  tank  of  12,000 
gallons  capacity,  with  4  tanks  of  1,500  gallons  capacity  in  series  for  recovery 
of  sludge  carried  from  aeration  tank.  From  each  of  the  first  two  settling 

22 


Abstract  Bibliography — 1915 

tanks,  sludge  is  pumped  back  to  the  inlet  of  the  aeration  tank  for  about  5 
minutes  in  every  half-hour,  while  the  other  two  require  pumping  back  only 
about  2  minutes  per  week.  Conclusions  have  not  been  reached  in  regard  to 
cost  of  operation  or  disposal  of  excess  sludge. 

94  Activated  sludge   is  capturing  the   popular  fancy.     EDITORIAL.    Eng.  & 
Contg.  44,  453.     Advises  engineers  to  stick  to  the  old  methods  of  sewage 

treatment  until  the  activated  sludge  process  has  definitely  made  good.  "Ac- 
tivated sludge  will  need  to  be  active  indeed  if  it  accomplishes  all  that  the 
public  expects  it  to  do." 

95  The  work  done  at  Salford  by  the  activated  sludge  process.     DISCUSSION. 
Surveyor  48,  629-30.     Sanitary  Record  56,  466-7.     Discussion  of  W.  H. 

DUCKWORTH'S  paper.  (Ref.  No.  93).  Waste  of  air  and  utilization  of  oxygen 
considered.  S.  RIDEAL  claims  the  rate  of  aeration  is  too  rapid  for  efficient 
absorption  of  the  oxygen.  Costs  are  paramount.  S.  BARWISE,  J.  B.  BARFORD, 

W.    D.    SCOTT-MONCRIEFF,    W.    H.    MAKEPEACE,    P.     GAUNT    and    J.     LAMB    also 

participated  in  the  discussion. 

96  Sewage  purification  by  forced  aeration.    EDITORIAL.    Sanitary  Record  56, 
463-4.     Comment  on  the  salient  points  in  W.   H.   DUCKWORTH'S  paper. 

(Ref.  No.  93).  The  paper  was  especially  directed  towards  establishing  the 
reliability  of  sewage  purification  by  forced  aeration,  and  also  to  indicate  from 
results  obtained  in  the  experiments:  (1)  The  minimum  time  of  aeration 
required  to  obtain  a  satisfactory  effluent.  (2)  Whether  the  method  is  liable 
to  be  affected  by  weather  conditions.  (3)  Whether  the  air  jets  would 
become  clogged  and  in  what  period  of  time.  (4)  The  minimum  amount 
of  air  necessary.  (5)  Whether  the  "continuous  flow"  method  was  possible 
and  preferable  to  the  "fill-and-draw"  plan.  (6)  If  the  process  as  a  whole 
was  an  economic  possibility. 

97  Chicago  activated  sludge  experiments.    NEWS  ITEM.      Eng.  Record  72,  768. 
Activated  sludge  experiments  will  soon  be  carried  on  intensively  by  the 

Sanitary  District  of  Chicago  with  the  stockyards  sewage,  $10,000  having 
recently  been  appropriated  by  the  trustees  for  that  purpose. 

98  Sewage  disposal  by  aeration.      EDITORIAL.     Surveyor  48,  645.     American 
results  are  reported  more  promptly  than  English.     Air  jets  can  be  used 

but  need  frequent  cleaning.     Proper  depth  of  tanks  still  an  unknown  factor. 

99  Activated  sludge.    W.  N.  BAKER.     Sanitary  Record  56,  487-8.    A  survey 
of  the  activated  sludge  experiments  conducted  at  various  places  in  the 

United  States.  This  method  of  sewage  treatment  involves  the  forced  aera- 
tion of  sewage  in  the  presence  of  accumulated  sludge,  and  appears  to  be  adapt- 
ed to  changes  of  season,  flood,  drought,  and  other  conditions.  (Cf.  Ref.  No.  60). 

100  Second  Annual  Report  of  the  Milwaukee  Sewerage  Commission.     T.  C. 

HATTON  and  W.  R.  COPELAND.  Pamphlet  pp.  188.  (Dec.  31,  1915).  Data 
from  reports  of  Chief  Engineer  HATTON  and  Chief  Chemist  COPELAND,  respect- 
ing the  activated  sludge  experiments  at  the  Jones  island  sewage  testing  sta- 
tion, for  the  year  ending  Dec.  31,  1915.  The  experiments  began  in  the  labora- 
tory using  a  glass  tube  6  ft.  long  by  1.5  in.  diam.;  next,  two  tanks  5  ft.  by  1 
ft.  by  10  ft.  deep  with  glass  windows  in  the  sides  were  tried;  then  a  tank 
32  ft.  by  10.5  ft.  by  9  ft.  deep  on  the  fill  and  draw  plan;  later  another  tank 
of  the  same  size  on  the  continuous  flow  plan,  this  being  the  first  continuous 
flow  operation  of  the  activated  sludge  process.  The  numerous  experiments 
made  with  these  tanks  were  so  encouraging  that  a  plant  to  handle  2  million 
gallons  per  day  was  decided  upon.  This  comprised  11  circular  reinforced 
concrete  tanks  30  ft.  diam.;  8  designed  for  aeration,  1  for  sedimentation, 
and  2  for  sludge  re-aeration.  The  aerating  tanks  were  so  baffled  that  a 
channel  114  ft.  long  was  provided  in  each,  78  filtros  plates  in  the  sloping 

23 


The  Activated  Sludge  Process 

bottom  of  each  channel  being  used  as  air  diffusers:  ratio  1  to  8.5.  The 
settlement  tank  had  a  hopper  bottom  terminating  in  a  4  ft.  diam.  cast-iron 
pipe  24  ft.  below  the  bottom  of  the  tank,  with  an  air  lift  for  removing  the 
sludge.  The  raw  sewage  passed  through  a  conduit  to  No.  1  aerating  tank, 
activated  sludge  in  the  desired  proportion  being  added  to  it  enroute,  the 
mixture  then  passing  through  each  of  the  8  aerating  tanks  in  rotation,  flowing 
a  total  of  912  lineal  feet.  With  a  4  hour  aeration  period,  the  estimated  ca- 
pacity of  the  plant  was  1,620,000  gallons  per  day;  with  a  3  hour  aeration 
period,  2,160,000  gallons  per  day.  Different  means  of  air  diffusion,  volumes 
of  air,  volumes  of  sludge,  etc.,  are  but  a  few  of  the  great  number  of  experi- 
ments made,  the  summarized  results  of  which  are  shown  in  a  mass  of  analyti- 
cal and  other  data  occupying  about  100  pages  of  the  report.  Numerous 
illustrations,  diagrams,  and  inserts  of  plans  also  accompany  the  report. 

101  Experiments  upon  the  purification  of  sewage  and  water  at  the  Lawrence 
Experiment  station  during  the  year  1915.     H.  W.  CLARK.     First  Annual 

Report  Mass.  State  Dept.  Health.  377-429.  Engineering  104,  99-100.  Expt. 
Sta.  Record  37,  787.  The  sewage  aeration  work  from  1912  to  date  is  briefly 
reviewed,  with  particular  reference  to  its  relation  to  the  activated  sludge 
process.  Investigations  begun  in  1913-14  have  been  continued  with  modifi- 
cations, the  results  being  shown  in  tabulated  data.  An  activated  sludge  tank 
without  slate  was  started  early  in  the  year  and  operated  with  3,  5,  8,  and  24 
hour  aeration  periods.  80%  of  the  3-hour  samples  and  all  of  the  others  were 
stable  on  incubation.  Sludge  investigations  showing  the  increase  in  N  and 
the  decrease  in  fats,  with  comment  on  its  fertilizer  value  are  also  given. 

102  Worcester   (Eng.)   sewage  works.     ANON.     Pamphlet   1915.     16  pages. 
Describes  a  visit  of  the  water  and  sewerage  commission  to  the  Salford 

fill  and  draw  activated  sludge  plant,  where  80,000  gallons  of  sewage  was 
being  treated  daily.  Perforated  pipes  with  holes  at  9  inch  intervals  distrib- 
uted the  air.  About  25%  of  sludge  was  carried,  with  the  following  cycle  of 
operations: — 1  hour  fill,  3  hour  aeration,  2  hour  settlement,  1  hour  emptying. 

1916 

103  Activated  sludge  sewage  treatment.     EDITORIAL.     Eng.  Record  73,  5-6. 
A  review  of  the  subject  covering  the  work  to  date  at  Manchester,  Eng., 

Milwaukee,  Wis.,  Brooklyn,  N.  Y.,  and  the  Chicago  stockyards.  The  articles 
of  the  past  year  contributed  by  DR.  FOWLER,  ARDERN  &  LOCKETT,  DR.  BARTOW, 
and  MR.  T.  C.  HATTON  are  discussed,  the  editor  summing  up  the  apparent 
advantages  of  the  process  as  (1)  the  ability  to  control  the  quality  of  the 
effluent,  (2)  freedom  from  offensive  odors,  (3)  small  plant  area  required,  (4) 
low  first  cost. 

104  Sewage  disposal  by  the  activated  sludge  process.    W.  B.  FULLER.     Am. 
City  14,  78-81.     A  brief  resume  of  the  process  with  illustrations  of  the 

Brooklyn  experimental  plant  for  sewage  disposal. 

105  The  activated  sludge  method  of  sewage  treatment.    ANON.  Munic.   Engr. 
50,  6-8.    A  brief  history  of  the  rapid  development  of  the  activated  sludge 

method  of  sewage  treatment,  abstracted  from  the  results  of  the  research  of 
PROF.  EDWARD  BARTOW,  of  the  Univ.  of  Illinois.  It  shows  that  there  is  much 
promise  in  this  latest  attempt  to  solve  the  great  problem  of  the  disposal 
of  the  sludge  resulting  from  this  method  of  sewage  treatment,  in  part  by 
destroying  some  of  it  in  the  treatment  process,  in  part  by  making  it  innocuous 
and  practically  inoffensive,  and  in  part  by  giving  it  some  value  as  a  fertilizer 
not  too  low  in  grade  for  practical  use. 

106  Sanitary  engineering  in  1915.     The  activated  sludge  method  of  sewage 
disposal.    ANON.     Engineer  121,  30-1.    A  general  review  of  the  activated 

sludge  work  during  the  year,  in  which  reference  is  made  to  the  plants  at 

24 


Abstract  Bibliography — 1916 

Manchester,  Eng.,  Salford,  Eng.,  Milwaukee,  Wis.,  and  Cleveland,  0.  The 
1915  articles  on  the  subject  by  ARDERN  &  LOCKETT  and  by  T.  C.  HATTON  are 
discussed. 

107  Activated  sludge  process  at  Wimbledon,  (Eng.)    EDITORIAL.   Surveyor  49, 
51.     Discussion  of  paper  by  C.  H.  COOPER.     (Ref.  No.  108).     Doubtful 

about  his  plan  of  mixing  aerated  effluent  with  raw  sewage,  returning  only 
a  small  amount  of  sludge,  but  agrees  with  him  that  it  is  not  so  much  intimate 
contact  of  air  with  sewage  as  thorough  mixing  of  activated  sludge  with 
sewage. 

108  Activated  sludge.     C.  H.  COOPER.     Surveyor  49,  55-6.     Aeration  experi- 
ments are  to  be  undertaken  at  Wimbledon  using  atomizers.    Anticipates 

cost  of  air  will  not  exceed  $5.50  per  million  gallons.  (Imp.)  Proposes  to 
eliminate  sludge,  using  instead  the  purified  effluent.  Statements  are  rather 
vague. 

109  Brooklyn's  fill-and-draw  tank  not  a  small  one.    W.  T.  CARPENTER.    Eng. 
Record  73,  121.     A  letter  to  the  editor  to  correct  an  impression  in  a 

recent  editorial.  (Ref.  No.  103).  The  size  of  the  tank  in  question  being  of 
16,000  gallons  capacity. 

110  British  and  American  patents  on  activated  sludge.    T.  C.  HATTON.    Eng. 
News  75,  189-90.     Chem.  Abst.  10,  1064.     U.  S.  Patent  1,139,024,  issued 

to  L.  C.  FRANK  (Ref.  No.  48)  and  four  British  patents  issued  to  JONES  & 
ATTWOOD,  (Ref.  No's.  3,  5,  10,  11),  have  identical  process  and  apparatus 
claims.  Americans  have  developed  the  continuous  flow  apparatus.  (Cf.  Ref. 
No.  129). 

111  Sewage  disposal  appliances.    JONES  &  ATWOOD,  LT'D.     Surveyor  49,  126. 
The  first  permanent  activated  sludge  plant  was  installed  at  the  Baguley 

Sanatorium,  Manchester,  Eng.,  being  of  20,000  gallons  capacity.  The  next 
plants  were  at  Stamford  and  Worcester,  Eng.,  where  half  the  flow  was  first 
treated,  then  all.  Worcester's  total  is  6  million  gallons  per  day. 

112  Pioneer  activated  sludge  plant  in  service.    NEWS  ITEM.    Eng.  Record  73, 
160.     The   Milwaukee   plant  when   operating  with   25%    sludge   in   the 

aerating  tanks  and  with  a  4  hour  running-through  period,  has  a  capacity  of 
1,620,000  gallons  per  day.  The  sedimentation  period  is  27  minutes  and  the 
velocity  of  flow  through  the  8  aerating  tanks,  covering  912  ft.  direct  travel, 
is  3.8  ft.  per  minute.  Decreasing  the  running-through  period  to  3  hours 
increases  the  capacity  to  2,160,000  gallons  per  day  and  the  velocity  to  5  ft. 
per  minute.  Costs  of  pumps,  meters  and  tanks  are  given. 

113  Purification  of  sewage  by  aeration  in  the  presence  of  activated  sludge.  II. 

E.  BARTOW.  Trans.  Am.  Inst.  Chem.  Engrs.  9,  161-8.  Jour.  Bad.  1,  111. 
Chew,.  Abst.  10,  2115.  A  continuation  of  the  experiments  in  the  concrete 
tanks  previously  referred  to,  (Ref.  No.  83)  dealing  particularly  with  the 
building  up  of  the  active  sludge,  and  the  diffusion  area  required.  The  compo- 
sition of  the  effluent  air,  the  N  in  the  sludge  and  results  of  pot  tests  with 
the  latter  as  fertilizer  are  also  given.  Mechanical,  chemical,  and  bacterio- 
logical features  of  the  process  are  considered,  the  future  of  which  is  very 
bright,  though  much  depends  upon  whether  the  sludge  can  be  economically 
recovered  as  fertilizer  material. 

114  First  annual  report  of  the  city  engineer  on  sewage  disposal,   City  olj 
Houston,  Texas.     E.  E.   SANDS.     Feb.  1,  1916.     Chem.  Abst.  10,  2015. 

5,000,000  gallons  of  untreated  sewage  cause  a  nuisance  at  White  Oak  Bayou, 
one-quarter  mile  from  the  business  section.  Experimental  work  with  two- 
story  settling  tanks,  aerated  contact  beds,  the  electrolytic  process  and  the 

25 


The  Activated  Sludge  Process 

activated  sludge  method  of  sewage  treatment  showed  the  superiority  of  the 
latter  method.  On  the  fill  and  draw  plan,  4  hours  aeration  with  0.437  cu.  ft. 
of  free  air  per  gallon  of  sewage  treated  per  hour,  secured  an  average  re- 
moval of  67%  total  organic  nitrogen,  95%  free  ammonia,  44%  total  organic 
matter,  90%  oxygen  consumed,  98%  dissolved  oxygen  consumed,  98%  sus- 
pended matter  and  95.8%  bacteria.  A  continuous  flow  tank  appeared  best 
adapted  to  local  conditions.  A  2-unit  and  a  4-unit  activated  sludge  plant 
have  been  designed.  Each  unit  is  expected  to  handle  the  sewage  from  37,100 
persons  or  an  average  flow  of  2,190  gallons  per  minute.  The  aeration  deten- 
tion period  of  the  sewage  will  be  1  hour  50  minutes  and  the  sludge  will  be 
aerated  for  3  hours.  The  tank  will  be  supplied  with  0.26  cu.  ft.  of  free  air 
per  minute  per  sq.  ft.  of  tank  surface.  Surplus  sludge  will  be  handled  on 
drying  beds  and  sold  to  market  gardeners.  The  estimated  construction  cost 
is  $378,000.  The  estimated  cost  for  disposal  is  $4.20  per  million  gallons  when 
the  plants  operate  at  full  capacity  and  serve  280,000  people. 

115  Activated   sludge   experiments   at  Brooklyn,   N.   Y.        ANON.        Munic. 

Eng'rg.  50,  73.  Refers  to  a  paper  by  G.  T.  HAMMOND  presented  at  a 
meeting  of  the  Am.  Assoc.  Adv.  Science  in  which  the  experiments  conducted 
during  1915  are  described.  The  work  done  does  not  justify  a  very  positive 
conclusion,  though  it  offers  considerable  promise. 

116  Success  of  the  activated  sludge  process  seems  assured.    EDITORIAL.    Eng. 
&  Contg.  45,  97-8.     The  critical  period  has  been  safely  passed,  both  at 

Milwaukee  and  Urbana,  these  plants  operating  well  through  the  cold  weather. 
The  process  appears  to  be  practical  for  cities  having  excess  of  2  million 
gallons  daily  flow  of  sewage.  Early  conclusions  subject  to  modification  and 
many  wrinkles  yet  to  iron  out. 

117  Summary  and  latest  results  on  experimental  work  on  activated  sludge  at 
Milwaukee,  Wis.     T.  C.  HATTON.    Eng.  &  Contg.  45,  104-8.     Contract 

Record  30,  382-5.  Surveyor  49,  308-9.  Expt.  Sta.  Record  35,  188.  A  paper 
before  the  Joint  Annual  Convention  of  111.  Section,  Am.  W.  W.  Assoc.  and 
111.  Soc.  of  Eng'rs.  and  Surveyors,  Urbana,  111.,  Jan.  27,  1916,  which  covers 
the  early  experiments,  data  on  air  diffusers,  functions  of  activated  sludge, 
effects  of  cold  weather  and  volume  of  air,  data  on  unit  quantities,  and  gen- 
eral conclusions. 

118  The  value  of  activated  sludge  as  a  fertilizer.     W.  D.  HATFIELD  and  E. 
BARTOW.     Univ.  III.  Bull.  14,  336-47.      (Water  Survey  Series  No.  13). 

Chem.  Abst.  11,  1711.  Activated  sludge  was  analyzed  and  found  to  contain 
greater  quantities  of  N  and  P  than  other  sewage  sludges.  The  best  evidence 
of  its  value  was  the  greater  growth  of  wheat,  lettuce  and  radishes  when  the 
sludge  was  used  as  a  fertilizer.  (Cf.  Ref.  No's.  84  and  444.) 

119  Sewage  purification  by  the  activated  sludge  process.  EDITORIAL.  Surveyor 
49, 143.    Comment  on  paper  by  DR.  G.  J.  FOWLER.    (Ref.  No.  120.)    Draws 

analogy  between  the  activated  sludge  process  and  sprinkling  filters.  Conserva- 
tion of  nitrogen  an  attractive  feature  of  the  activated  sludge  process. 

120  The  activated  sludge  process  of  sewage  purification.    G.  J.  FOWLER.    Sur- 
veyor 49,  148-51.    Expt.  Sta.  Record  35,  188.    A  summary  of  the  present 

knowledge  of  both  the  scientific  and  practical  phases  of  the  activated  sludge 
process  of  sewage  purification.  It  has  been  shown  by  DR.  BARTOW  and  DR. 
ARDERN  that  it  is  not  necessary  to  nitrify  sewage  while  building  up  sludge. 
Activated  sludge  contains  no  algae.  Refers  to  American  results  by  DR. 
BARTOW,  T.  C.  HATTON,  et  al.  JONES  &  ATTWOOD  first  developed  air  lifts  which 
did  not  give  sufficient  aeration;  then  nozzles,  which  clogged;  finally,  porous 
stone  diffusers,  which  proved  satisfactory.  The  results  being  obtained  in  the 
Davyhulme  and  the  author's  laboratories  indicate  a  possible  fixation  of  atmos- 
pheric nitrogen.  Sludge  drying  is  a  problem  for  the  engineers.  A  list  of 
23  references  to  the  subject  is  given. 

26 


Abstract  Bibliography — 1916 

121  The  activated  sludge  process  of  sewage  treatment.    G.  J.  FOWLER.    Can. 
Engr.  30,  227-8.    Surveyor  49,  405-6.    Jour.  Bact.  1,  251.    Chem.  Abst.  10, 

1064.  In  a  written  discussion  of  the  paper  by  RUDOLPH  HERING  on  the  "Dis- 
posal of  Suspended  Matter  in  Sewage,"  DR.  FOWLER  sketches  the  historical  de- 
velopment of  the  activated  sludge  process  and  dwells  on  the  effect  of  adding 
"M7"  bacterial  cultures  in  the  presence  of  iron  in  solution.  Much  research  is 
still  required.  The  work  of  MR.  HATTON  at  Milwaukee,  and  DR.  BARTOW  at 
Urbana  is  referred  to. 

122  Activated  sludge  experiments  at  Milwaukee,  Wis.    T.  C.  HATTON.    Eng. 
News  75,  262-3,  306-8.     A  number  of  activated  sludge  tanks  of  different 

designs  have  been  operated  by  different  methods  with  such  promising  results 
that  a  start  has  been  made  on  the  construction  of  a  100,000,000  gallon  plant. 
Filtros  was  the  air  diffuser  used  in  some  of  the  tanks,  the  ratio  of  plate  area 
to  tank  area  being  1  to  6.6.  Varied  and  extended  studies  of  the  activated  sludge 
process  of  sewage  treatment  conducted  during  the  past  year  are  summarized 
and  conclusions  drawn  as  to  general  results  and  costs.  With  a  continuous  flow 
tank  an  effluent  stable  for  5  days,  90%  reduction  of  suspended  matter  and  95% 
removal  of  bacteria  at  20°  C.,  has  been  obtained  by  using  1.75  cu.  ft.  of  air 
per  gallon  of  sewage,  with  a  4  hour  aeration  in  the  presence  of  20%  activated 
sludge.  Basing  the  results  upon  the  operation  of  a  50,000,000  gallon  plant, 
the  estimated  cost  will  be  $4.38  per  million  gallons  including  all  overhead  and 
boiler-room  charges,  but  excluding  engine-room  and  plant  attendance  and  the 
disposal  of  the  sludge.  Plant  construction  costs  are  estimated  at  $18,000  per 
million  gallons. 

123  News  item.    Eng.  News  75,  293.    A  150,000  gallon  activated  sludge  plant 
to  treat  packing-house  sewage  was  put  into  operation  the  latter  part  of 

January  by  the  Sanitary  District  of  Chicago,  under  the  direction  of  LANGDON 
PEARSE,  Division  Eng.,  and  DR.  ARTHUR  J.  LEDERER,  Chemist. 

124  The  oxidation  of  sewage  without  the  aid  of  filters.    E.  ARDERN  and  W.  T. 
LOCKETT.    Jour.  Soc.  Chem.  2nd.  35,  153-5.     Chem.  Abst.  10,  2015.     Dis- 
cussion of  a  previous  paper   (Ref.  No.  71)   in  which  DR.  G.  J.  FOWLER,  MR. 
HALLIWELL,  MR.  P.  GAUNT  and  MR.  W.  THOMPSON  participated.    Mr.  Ardern 
in  response,  said,  among  other  things: — "With  regard  to  the  adoption  of  wire 
meshes  as  air  diffusers,  this  was  possibly  a  feasible  proposition.     It  was  a 
question  of  durability.     Other  suggestions  had  been  the  adopton  of  porous 
metal,  cocoanut  matting  and  asbestos  fiber,  but  up  to  the  present  nothing  better 
had  been  found  than  a  porous  mineral  septum.     Most  of  the  tiles  used  up  to 
the  present  in  the  course  of  the  experiments  under  consideration,  had  been 
made  of  silica  which  was  dried  and  burned." 

125  Sewage  treatment  by  the  activated  sludge   process.     HENRY  TRAXLER. 
Iowa  Eng.  Soc.  Proc.  28,  80-5.  (1916).    Chem.  Abst.  11,  509.     In  a  brief 

review  of  the  history  of  the  process,  the  author  states  that  "In  this  country 
BLACK  and  PHELPHS  in  New  York;  CLARK,  GAGE,  and  ADAMS  at  the  Mass. 
State  Board  of  Health  experiment  station  at  Lawrence,  were  the  first  to  obtain 
promising  results."  DR.  FOWLER'S  visit  to  Lawrence  is  referred  to  and  the 
subsequent  work  of  ARDERN  &  LOCKETT  at  Manchester,  Eng.,  whose  first  ex- 
periments made  use  of  5-pint  bottles.  DR.  BARTOW'S  work  at  the  Univ.  of  111. 
in  1914,  and  MR.  T.  C.  HATTON'S  at  Milwaukee  in  1915  followed.  Brief  con- 
siderations of  the  results  obtained  to  date  (Feb.  1916)  are  given. 

126  Air  diffusers  tested  at  Milwaukee  sewage  plant.     T.  C.  HATTON.     Eng. 
Record  73,  255.    Chem.  Abst.  11,  80.    Results  of  experiments  on  activated 

sludge.  Tabulated  data  obtained  with  open  air  jets,  Monel  metal  cloth,  filtros 
and  kieselguhr  are  given.  Filtros  plates,  composed  of  quartz  sand  baked,  of 
uniform  porosity,  have  given  the  most  satisfactory  results. 

27 


The  Activated  Sludge  Process 

127  Apparatus  for  aerating  sewage  and  other  foul  liquids.    R.  AMES,  Brighton, 
Eng.     British   Patent   104,361,   Feb.   25,   1916.     Jour.   Soc.   Chem.   Ind. 

36,  519.  The  apparatus  consists  of  a  circular  tank  in  which  there  is  a  central 
standpipe  supporting  a  chamber  carrying  horizontal  radial  arms,  capable  of 
being  revolved  above  the  level  of  the  liquid  in  the  tank.  The  sewage  enters 
by  a  pipe,  in  which  it  is  mixed  with  compressed  air,  along  the  bottom  of  the 
tank  to  the  central  standpipe,  from  openings  in  the  bottom  of  which  the  sewage 
passes  into  the  body  of  the  tank.  Air  is  supplied  to  the  chamber  carrying  the 
radial  arms,  and  pipes  depend  from  these  arms  nearly  to  the  floor  of  the  tank, 
with  atomizers  attached  to  their  ends.  The  atomizers  consist  either  of  a  metal 
casing  containing  a  porous  block,  or  layers  of  wire  gauze,  or  of  a  hollow  metal 
block  with  narrow  slots.  The  radial  arms  are  rotated  by  the  pressure  of  the 
escaping  air  on  the  liquid,  or  by  mechanical  means.  The  purified  liquid  is  drawn 
off  intermittently  or  continuously.  (Cf.  Brit.  pat.  110,197,  Ref.  No.  194). 

128  Activated  sludge  treatment  of  packinghouse  wastes.     EDITORIAL.     Sur- 
veyor 49,  234.    ARMOUR  &  Co.  have  a  20,000  gallon  continuous  flow  plant, 

while  that  of  the  Sanitary  District  of  Chicago  will  treat  150,000  g.  p.  d. 

129  Is  the  activated  sludge  process  of  sewage  treatment  to  be  patented  again? 
ANON.    Eng.  &  Contg.  45,  208-9.    In  a  recent  paper  by  MR.  T.  C.  HATTON 

before  the  Indiana  Engrs.  Soc.,  it  was  stated  that  DR.  G.  J.  FOWLER  of  England 
was  the  real  discoverer  of  the  process — if  it  can  be  considered  a  discovery 
rather  than  a  combination  of  well  known  principles — and  that  his  interests 
were  turned  over  to  JONES  &  ATTWOOD  who  secured  British  patents  on  the 
art.  In  the  meantime,  MR.  L.  C.  FRANK  of  Washington,  D.  C.,  was  granted  a 
U.  S.  patent  on  the  process  covering  particularly  the  continuous  flow  principle. 
With  so  much  similarity  between  this  patent  and  JONES  &  ATTWOOD'S  pending 
applications  for  U.  S.  patents,  it  would  appear  as  though  the  U.  S.  would  not 
be  warranted  in  granting  the  latter.  Statement  is  also  made  that  the  majority 
of  the  apparatus  patented  in  England  by  JONES  &  ATTWOOD  is  not  essential  to 
the  proper  operation  of  the  process  (Cf.  Ref.  No.  110). 

130  The  aeration  or  activation  of  sewage.     G.  T.  HAMMOND.     Surveyor  49, 
255-7.     A  history  of  sewage  aeration  processes  including   BLACK  and 

PHELPS'  work  at  Brooklyn.  Following  these  experiments,  activated  sludge 
tests  were  begun  at  Brooklyn  in  a  tank  of  16,000  gallon  scapacity.  Pipe  grids 
with  1-16  in.  holes,  overlaid  with  7.5  in.  of  broken  stone  served  as  air  diffusers. 
Fill  and  draw  tests  with  5  hours  aeration  and  7  volumes  of  air  per  volume  of 
sewage,  gave  a  stability  of  62  and  nitrates  1.2  p.  p.  m.  Next  experiments  were 
on  the  continuous  flow  plan  using  a  tank  4.5  ft.  diam.  by  8  ft.  deep,  of  about 
1,000  gallons  capacity,  with  a  lower  chamber  for  aeration  and  an  upper  one 
for  settling,  the  latter  occupying  about  1-10  the  tank.  Using  carborundum 
discs  for  air  diffusers,  air  at  the  rate  of  0.7  cu.  ft.  per  minute,  8  hours  aeration 
and  45  minutes  settlement,  the  stability  was  low  and  no  nitrates  formed. 
With  4  hours  aeration  and  23  minutes  settlement,  results  were  unsatisfactory. 

131  The  fundamental  principles  of  the  activated  sludge  process  of  sewage 
treatment.    T.  C.  HATTON.    Eng.  and  Contg.  45,  235-6.     Eng.  News  75, 

503.  Jour.  Bact.  1,  250.  Chem.  Abst.  10,  1064,  3122.  Ind.  Sanit.  and  Water 
Supply  Assoc.  1916.  In  a  paper  before  the  Indiana  Engineers  Soc.,  Mr.  Hatton 
points  out  that  the  activated  sludge  process  should  not  be  confused  with  the 
kind  of  artificial  aeration  of  sewage,  attempted  from  time  to  time  in  the  past, 
which  made  no  use  of  the  sludge  as  an  aid  to  oxidation.  He  thinks  that  the 
activated  sludge  process  depends  on  the  presence  of  biologic  life  in  the  sludge 
under  aerobic  conditions  and  that  the  definition  given  by  MR.  W.  R.  COPELAND 
is  the  best  one,  viz.: — "The  sludge  embodied  in  sewage  and  consisting  of  sus- 
pended organic  solids,  including  those  of  a  colloidal  nature,  when  agitated  with 
air  for  a  sufficient  period,  assumes  a  flocculent  appearance  very  similar  to 
small  pieces  of  sponge.  Aerobic  and  facultative  aerobic  bacteria  gather  in 
these  flocculi  in  immense  numbers— from  12,000,000  to  14,000,000  per  c.  c.— 

28 


Abstract  Bibliography — 1916 

some  having  been  strained  from  the  sewage  and  others  developed  by  natural 
growth.  Among  the  latter  are  species  which  possess  power  to  decompose 
organic  matter,  especially  of  an  albuminoid  or  nitrogenous  nature,  setting  this 
nitrogen  free;  and  others,  absorbing  this  nitrogen,  convert  it  into  nitrites  and 
nitrates.  These  biological  processes  require  time,  air  and  favorable  environ- 
ment, such  as  suitable  temperature,  food  supply  and  sufficient  agitation  to 
distribute  them  throughout  all  parts  of  the  sewage." 

132  Report  of  the  board  of  engineers  on  sewage  disposal,  to  the  cities  of 
Pasadena,  South  Pasadena,  and  Alhambra,  Calif.    R.  V.  ORBISON,  C.  E. 

HEWES  and  JOHN  MACMILLAN.  Pamphlet,  pp.  54.  (March  27,  1916.)  The 
activated  sludge  process  is  described,  and  an  account  of  the  early  experi- 
ments given.  Sludge  disposal  and  cost  problems  are  discussed  in  connection 
with  the  possibility  of  a  trial  of  the  process. 

133  Some  observations   on   the   treatment   of   sewage   by   activated   sludge. 
W.  H.  DUCKWORTH.    Surveyor  49,  352-4.    Chem.  Abst.  10,  3122.    A  review 

of  results  at  other  places  and  reference  to  the  Salford  experiments.  Air  was 
not  measured.  Jets  clogged  rapidly.  Sludge  recovered  quickly  from  inhibitory 
effect  of  trade  wastes.  The  author  considers  the  activated  sludge  process  sim- 
ilar to  an  "intensified  contact  bed."  The  Salford  plant  treating  55,000  g.  p.  d., 
gave  satisfactory  results  in  winter.  Over-aeration  is  possible.  As  much 
sludge  is  produced  as  from  chemical  precipitation.  Discussion  followed  in 
which  there  participated,  A.  R.  BLEAZARD,  R.  J.  McKENN,  W.  M.  JONES, 
ARTHUR  BOWES  and  TOM  FOGG. 

134  The  activated   sludge  process   of   sewage   purification.     G.   J.    FOWLER. 
Jour.  Inst.  Sanit.  Engrs.  20,  29-38.     DISCUSSION,    (Same  journal)    20, 

39-49.  "The  activated  sludge  process  of  sewage  purification  may  be  described 
as  a  process  of  intensive  bacterial  oxidation — and  would  appear  to  consist 
broadly  of  three  operations:  a  clotting  or  clarifying  action;  a  rapid  carbon 
oxidation  process,  and  finally,  nitrification."  The  scientific  researches  of 
ARDERN  &  LOCKETT  and  of  DR.  BARTOW  and  his  associates  are  referred  to,  as 
well  as  the  engineering  developments  at  Davyhulme,  Salford,  Worcester  and 
Stamford  in  England,  and  Milwaukee,  Baltimore,  Cleveland,  Houston  and 
Chicago  in  the  United  States,  and  Regina  in  Canada.  Quotations  from  the 
reports  of  the  several  engineers  in  charge  of  the  various  plants  are  numerous. 
Of  the  future  "Much  work  remains  to  be  done  on  both  the  scientific  and  tech- 
nical sides  *  *  *"  MR.  A.  P.  I.  COTTERELL,  DR.  McGowAN,  DR.  E.  ARDERN, 
MR.  G.  B.  KERSHAW,  MR.  C.  SMITH  and  MR.  H.  A.  ROECHLING  participated  in 
the  discussion,  bringing  up  questions  of  costs,  effects  of  varying  amounts  of  air, 
supervision  of  the  process,  sludge  treatment  and  revenues  therefrom,  and  the 
effects  of  trade  wastes  on  the  process. 

135  The  latest  method  of  sewage  treatment.    E.  BARTOW.    Jour.  Boston  Soc. 
C.  E.  3,  153-70.    Jour.  Am.  Waterworks  Assoc.  3,  327-44,  869-70.    Chem. 

Abst.  10,  3122.  Expt.  Sta.  Record  35,  787.  Relates  to  the  activated  sludge 
process  and  the  experiments  made  at  Urbana,  111.  Sludge  could  be  built  up 
by  frequently  changing  the  sewage  rather  than  waiting  for  complete  nitrifica- 
tion before  making  a  change.  The  fertilizer  value  of  the  sludge  has  been 
shown  by  experiments  with  wheat.  Discussion  by  W.  F.  WILCOX  relates  to 
the  adaptation  of  a  septic  tank  by  dividing  it  into  16  chambers,  each  one  the 
inverted  frustum  of  a  pyramid,  so  that  5  to  7  million  gallons  per  day  were 
satisfactorily  treated. 

136  The  extent  to  which  sewage  can  be   purified  by  practical  methods  of 
artificial  treatment  now  in  use.     H.  P.  EDDY.       Proc.  Eng.  Soc.  West. 

Penn.  32,  226-70.  Surveyor  50,  238-41.  With  respect  to  the  activated  sludge 
process,  the  following  features  are  considered:  theory  of  action;  method  of 
operation;  aeration;  sedimentation;  sludge  handling;  character  of  effluent; 
application  to  trade  wastes;  and  costs.  A  brief  description  of  the  Milwaukee 

29 


The  Activated  Sludge  Process 

experiments  are  given.  The  method  produces  a  clear,  sparkling,  well-oxidized 
effluent  and  its  bacterial  efficiency  and  power  to  oxidize  and  remove  organic 
matter,  apparently  approaches  that  of  the  sand  filter. 

137  Trial  activated  sludge  unit  at  Cleveland,  O.    R.  W.  PRATT.     Eng.  News 
75,  671-2.     Description  of  a  million  gallon  plant  operated  on  the  contin- 
uous flow  principle,  4  hour  aeration  period,  half-hour  settlement.     The  tank 
is  60  ft.  long,  30  ft.  wide  and  15  ft.  deep,  divided  into  6  compartments  each 
9.5  ft.  by  30  ft.    Four  compartments  are  used  for  aerating,  one  for  maintaining 
activity  of  the  sludge  and  one  for  sedimentation.     Filtros  is  used  as  the  air 
diffuser,  covering  25%  of  the  tank  bottom  area. 

138  Give  conclusions  on  activated  sludge  tests.     T.  C.  HATTON  and  W.  R. 
COPELAND.     Eng.  Record  73,  489.     Surveyor  49,  486.     Chem.  Abst.  10, 

3122.  Notes  from  an  elaborate  report  of  the  findings  at  the  Milwaukee  Sewage 
Testing  Station  in  the  report  of  the  Milwaukee  Sewerage  Commission  for  1915. 
(Cf.  Ref.  No.  100.) 

139  Purification  of  sewage  by  compressed  air.      — .  — .  BOWES.     Jour.  Soc. 
Chem.  Ind.  35,  suppl.  30.     British  Patent  Application  5,215,  April  10, 

1916. 

140  Plans  prepared  for  Houston,  Texas,  sewage  disposal  plant.    NEWS  ITEM. 
Eng.  Record  73,  561.    The  north  side  plant  has  been  designed  to  accommo- 
date an  average  daily  flow  of  12,600,000  gallons  and  the  south  side  plant 
6,300,000  gallons.     The  estimated  cost  of  disposal  plants  and  pipe  lines  is 
$639,000  and  the  operating  cost  is  given  as  $61,939  per  annum. 

141  Purification  of  sewage  by  activated  sludge  in  winter  at  the  sewage  test- 
ing station,  Milwaukee,  Wis.     W.  R.  COPELAND.     Eng.  and  Contr.  45, 

386-7.  Jour.  Ind.  Eng.  Chem.  8,  642-3.  Jour.  Bact.  1,  457.  Jour.  Soc.  Chem. 
Ind.  35,  904.  Chem.  Abst.  10,  2260.  The  winter  temperature  of  Milwaukee 
sewage  averages  about  51°  F.  (10.5°  C.)  and  occasionally  falls  to  40°  F. 
(4.5  C.)  or  lower.  By  increasing  the  air  supply  from  1.6  to  2.3  cu.  ft.  per 
gallon  of  sewage,  it  has  been  possible  to  remove  about  90%  of  the  bacteria 
and  suspended  matter  by  the  continuous  flow  activated  sludge  process.  The 
sludge  contains  about  98%  of  water,  but  this  can  be  reduced  to  75%  by  pressing, 
without  the  addition  of  lime,  and  the  sludge  press-cake  is  easily  handled  and 
can  be  converted  into  fertilizer.  On  a  10%  moisture  basis  the  sludge  contains 
about  5%  of  nitrogen  calculated  as  ammonia,  1.75%  of  available  phosphoric 
acid,  and  0.4%  of  potash.  It  is  estimated  that  one  million  gallons  of  Milwaukee 
sewage,  containing  from  260  to  440  parts  per  million  of  suspended  matter, 
will  yield  3,000  to  4,000  gallons  of  sludge  containing  98%  water,  which  is 
equivalent  to  about  half  a  ton  on  a  10%  moisture  basis.  The  sludge  is  being 
dewatered  in  a  WORTHINGTON  press.  It  is  estimated  that  it  will  cost  $5  to  $6 
to  dry  and  deliver  to  the  customer  a  sludge  worth  $10  to  $12.  With  the  out- 
side temperature  at  times  as  low  as  -15°  F.  (-26.1°  C.)  and  the  temperature 
of  the  sewage  on  a  few  occasions  reaching  34°  F.  (1.1°  C.),  good  bacterial 
removal  and  clarification  was  maintained. 

142  Chemical   observations   on   the   activated   sludge    process   as   applied   to 
stockyard  sewage.     A.  LEDERER.     Eng.  and  Contr.  45,  388.     Jour.  Ind. 

Eng.  Chem.  8,  652.  Jour.  Bact.  1,  457.  Chem.  Abst.  10,  2260.  The  stock- 
yards waste  lends  itself  readily  to  the  process,  though  the  free  oxygen  demand 
is  approximately  8  to  10  times  greater  than  the  domestic  sewage  of  Chicago. 
Temperatures  vary  between  60°  and  90°  F.  throughout  the  year  at  the  Center 
Ave.  outlet,  and  even  in  the  coldest  winter  weather  the  fall  of  temperature  in 
the  plant  is  only  a  few  degrees.  The  removal  of  colloidal  matter  was  the  only 
immediate  indication  of  accomplished  oxidation.  With  turbidities  of  10  parts 
per  million  or  less  the  effluent  is  stable.  The  quantity  of  settling  suspended 
matter  in  the  effluent  merely  indicated  the  efficiency  of  the  settling  process 
and  has  nothing  to  do  with  the  activated  sludge  process  proper. 

30 


Abstract  Bibliography — 1916 

143  Status  of  activated  sludge  sewage  treatment.     G.  T.  HAMMOND.     Eng. 
News  75,  798-800.     Chem.  Abst.  10,  2115.     Expt.  Sta.  Record  35,  490. 

After  visits  to  five  working-scale  plants,  the  author,  who  has  been  in  engi- 
neering charge  of  the  activated  sludge  experiments  at  Brooklyn,  draws  some 
noteworthy  conclusions  regarding  the  probable  desirability  of  preliminary 
screening,  the  apparent  advantages  of  pipe-grid  as  against  porous  plate  dif- 
fusers,  the  uncertainty,  but  great  importance  of  sludge  recovery  for  fertilizer 
base  and  of  sludge  dewatering.  He  considers  the  activated  sludge  process, 
while  promising,  as  still  in  the  early  experimental  stage,  but  fortunately  the 
experiments  are  on  a  large  scale  and  in  charge  of  able  men.  Illustrations  of 
plants  at  Brooklyn,  Cleveland,  Milwaukee,  Chicago  and  Baltimore  accompany 
the  article. 

144  Activated  sludge  Problems.     EDITORIAL.     Eng.  News  75,  809-10.     Com- 
menting on  the  article  by  GEO.  T.  HAMMOND  (Ref.  No.  143),  it  is  noted 

that  the  activated  sludge  process  combines  clarification,  oxidation,  and  bac- 
terial reduction  in  a  single  tank  or  series  of  them.  The  great  question  is  that 
of  costs,  though  that  of  air  supply  seems  to  be  a  critical  matter.  There  may  be 
various  difficulties  besides  that  of  final  sludge  disposal. 

145  Milwaukee's   activated    sludge   investigations.     R.    0.    WYNNE-ROBERTS. 
Can.  Engr.  30,  473-6,  561-5.     Chem.  Abst.  10,  3123.     A  resume  of  results 

of  experiments  carried  on  during  the  year  1915  by  the  Milwaukee  Sewerage 
Commission.  Analyses  are  given.  (Cf.  Ref.  No.  100.) 

146  Activated  sludge  at  Houston,  Tex.    ANON.    Munic.  Jour.  40,  585-8.     Ex. 
periments  on  this  method,  together  with  Imhoff  tanks,  aerated  contact 

beds  and  electrolytic  tanks.  Methods  and  results  with  activated  sludge.  Plans 
adopted  for  permanent  plant. 

147  Sewage  disposal  by  the  activated  sludge  process.    EDITORIAL.    Surveyor 
49,  480.    Comment  on  the  Milwaukee  results  as  noted  in  ref.  No.  138  .  A 

valuable  feature  of  the  activated  sludge  process  is  the  possibility  of  varying 
the  degree  of  purification  by  altering  the  volume  of  air  applied  or  the  aeration 
period.  The  degree  of  purification  should  first  be  fixed  and  the  plant  built  to 
give  this  purification. 

148  Activated  sludge  process  on  stockyards  sewage.    A.  LEDERER.    Eng.  News 
75.  932.     The  object  of  this  short  paper  is -to  elaborate  certain  facts  of  a 

chemical  and  biologic  nature  which  have  presented  themselves  in  the  course 
of  operations,  and  not  to  furnish  any  prescription  for  the  treatment  of  stock- 
yards waste.  The  work  indicates  that  the  temperature  of  the  liquid  treated 
will  be  a  controlling  factor. 

149  Tanks   for   the   purification   of   sewage.      T.    CAINK.      Worcester,    Eng. 
British  Patent  105,654,  May  20,  1916.     Jour.  Soc.  Chem.  Ind.  36,  611. 

Chem  Abst.  11,  2248.  The  apparatus  is  designed  to  be  used  in  the  purification 
of  sewage  by  the  activated  sludge  process  and  consists  of  a  tank  divided  into 
several  bays  in  series  and  covered  with  an  air-tight  roof  which  prevents  the 
air  injected  by  the  diffusers  from  escaping  directly  into  the  atmosphere,  but 
deflects  it  horizontally  to  an  exit,  whereby  circulation  of  the  sewage  in  the 
tank  is  set  up  to  effect  more  efficient  aeration.  The  tank  is  filled  to  the  roof 
with  sewage.  Air  is  admitted  along  the  bottom  of  one  side  of  each  bay  and 
imparts  to  the  sewage  a  vertical  circulatory  motion,  which  is  aided  by  suitable 
guiding  baffles  arranged  so  as  to  prevent  deposition  of  the  solids  on  the  floor 
of  the  bays.  In  another  form,  the  tank  is  divided  into  a  number  of  parallel 
bays  and  air  is  supplied  along  the  side  of  the  first  bay  only,  parallel  to  the 
direction  of  the  flow  of  the  sewage.  The  dividing  walls  between  the  bays 
have  openings  at  the  top  and  bottom  to  permit  of  the  passage  of  air  to  and 
fro  at  right  angles  to  the  flow  of  the  sewage.  This  imparts  a  spiral  motion 
to  the  sewage  in  the  tank. 

31 


The  Activated  Sludge  Process 

150  Activated  sludge.    EDITORIAL.     Can.  Engr.  30,  581.     Briefly  reviews  the 
introduction  of  the  process  by  DR.  FOWLER,   (suggested  to  him  by  DR. 

MACLEAN  WILSON)  and  ARDERN  &  LOCKETT,  concluding  with  this  paragraph: 
"The  comprehensive  experiments  made  at  Milwaukee  have  so  fully  confirmed 
the  statements  made  by  ARDERN  &  LOCKETT,  that  there  remains  but  little  doubt 
in  the  minds  of  sanitarians  generally,  that  we  are  to  witness  a  great  revolu- 
tion in  the  methods  of  sewage  treatment,  and  in  the  standards  of  purification 
which  will  in  the  future  be  attainable  in  ordinary  everyday  practice." 

151  Sewage  disposal  by  the  activated  sludge  process.     T.  C.  HATTON.     Can. 
Engr.  30,  590-3.     Chem.  Abst.  10,  3123.     The  activated  sludge  process  is 

compared  with  sprinkling  filters,  contact  beds,  etc.,  from  a  biological  point 
of  view  and  from  the  standpoint  of  relative  areas  required.  The  effect  of 
varying  volumes  of  air,  plant  design,  and  sludge  handling  are  discussed,  and 
the  results  of  some  of  the  Milwaukee  experiments  are  given. 

152  Manurial  value  of  sewage  sludge.     G.  MUMFORD.     Jour.  Bd.  Agric.  23, 
129-35.     Jour.  Soc.  Chem.  Ind.  35,  647.     A  sample  of  activated  sludge 

obtained  at  Manchester  from  domestic  sewage  lost  69.8%  on  ignition,  and 
contained  4.3%  phosphoric  acid  and  5.5%  nitrogen.  Some  samples  contained 
as  much  as  6  or  7%  nitrogen,  the  high  nitrogen  content  being  accounted  for 
by  assuming  that  the  solid  particles  of  sludge  assimilate  nitrogen  from  the 
liquid  portion,  the  effluent  holding  very  little  matter  in  suspension.  The  nitro- 
gen of  the  sludge  is  in  a  readily  available  condition. 

153  Activated  sludge  at  Milwaukee.    T.  C.  HATTON.    Munic.  Jour.  40,  785-7, 
824-5,  830.     Chem.  Abst.  10,  2491.     In  a  paper  before  the  N.  Y.  State 

Conference  of  Mayors  and  other  City  Officials,  Mr.  Hatton  stated  that  the 
Milwaukee  sewage  could  be  treated  with  1.75  cu.  ft.  of  free  air  per  gallon 
of  sewage,  with  4  hours  contact  in  the  presence  of  20%  activated  sludge. 
Filter-pressing  of  the  sludge  is  probably  feasible,  followed  by  drying.  The 
results  obtained  at  Milwaukee  are  outlined.  MR.  G.  D.  HOLMES  in  discussion 
adds  that  the  great  problem  yet  to  be  solved  is  the  disposal  of  the  watery 
sludge  without  offense. 

154  Activated   sludge  sewage  disposal.     EDITORIAL.     Munic.  Jour.   40,   833. 
Comments  on  MR.  T.  C.  HATTON'S  paper.     (Ref.  No.  153.)     Intimates 

that  offensive  odors  may  arise  on  drying  the  sludge  and  that  at  present  the 
process  is  too  expensive  for  small  cities.  Considers  plant  costs  as  compared 
with  other  processes  and  suggests  caution  in  adopting  the  method,  notwith- 
standing the  promising  nature  of  it. 

155  Artificial  means  of  sewage  treatment.    ANON.    Eng.  &  Contg.  45,  581-6. 
Chem.  Abst.  10,  2489.    From  a  paper  by  MR.  H.  P.  EDDY  presented  at  a 

meeting  of  the  Eng.  Soc.  of  West.  Penn.,  which  discusses  the  general  principles 
of  sewage  treatment.  The  activated  sludge  method  is  still  in  the  experimental 
stage,  with  possibility  of  high  cost  of  power  and  the  commercial  possibilities 
yet  to  be  demonstrated.  The  results  of  the  different  methods  of  sewage 
treatment  are  compared  briefly.  (Cf.  Ref.  No.  136.) 

156  Aeration  of  sewage  in  the  presence  of  activated  sludge.    E.  J.  FORT.    Jour. 
Ind.  Eng.  Chem.  8,  643.    Chem.  Abst.  10,  2260.    Reviews  the  experiments 

at  Brooklyn  with  the  16,000  gallon  aerator  tank  in  the  fall  of  1915,  this  tank 
supporting  7%  inches  of  broken  stone  on  a  grid,  and  operated  both  on  the 
continuous-flow  and  the  fill-and-draw  plan.  Tabulated  results  with  and  with- 
out activated  sludge  are  given.  The  author  believes  that  the  engineer  is  not 
yet  warranted  in  recommending  the  activated  sludge  process  for  general 
adoption. 

157  Activated  sludge  experiments  at  the  sewage  disposal  plant,  Baltimore. 

C.  W.  HENDRICK.    Jour.  Ind.  Eng.  Chem.  8,  645.     Chem.  Abst.  10,  2260. 
Reviews  the  laboratory  and  the  larger  experiments  and  gives  some  tabulated 

32 


Abstract  Bibliography — 1916 

results.  Air  diffuser  troubles  are  cited  with  special  reference  to  that  caused 
by  the  oil  which  is  carried  along  from  the  compressor.  The  possibility  of 
purifying  sewage  by  the  activated  sludge  method  is  shown,  but  additional 
experiments  are  recommended. 

158  Composition  of  the  effluent  air  from  an  activated  sludge  tank.     F.  N. 

CRAWFORD  and  E.  BARTOW.  Jour.  Ind.  Eng.  Chem.  8,  646-7.  Chem.  Abst. 
10,  2260.  The  carbon  dioxide  increases  from  4.3  parts  per  10,000  in  the  influent 
air  to  36  to  40  in  the  effluent  air.  The  oxygen  decreases  from  20.5%  to  19.3%. 
About  5%  of  the  oxygen  in  the  air  is  therefore  used  in  the  process.  (Cf.  Ref. 
No.  335.) 

159  Sewage  disposal  experiments  at  Brockton,  Mass.     R.  S.  WESTON.     Jour. 
Ind.  Eng.  Chem.  8,  647-8.    Jour.  Soc.  Chem.  Ind.  35.  904.    Science,  N.  S. 

44.  322.  Chem.  Abst.  10,  2261.  The  activated  sludge  process  promises  relief 
for  over- worked  filter  beds;  it  does  not  seem  to  be  practical  to  use  it  alone. 
Fill  and  draw  activated  sludge  tank,  followed  by  sand  bed  at  500,000  gallon 
rate  gave  excellent  results.  Continuous  process  now  being  tried  for  clarifica- 
tion alone  with  good  results.  Aeration  period  at  least  4  hours.  The  experi- 
ments are  being  continued. 

160  The  activated  sludge  process  in  the  treatment  of  tannery  wastes.    H.  P. 

EDDY  and  A.  L.  FALES.  Jour.  Ind.  Eng.  Chem.  8,  648.  Jour.  Am.  Leather 
Chem.  Assoc.  11,  441-9.  Jour.  Soc.  Chem.  Ind.  35,  905.  Surveyor  50,  282-4. 
Chem.  Abst.  10,  3123.  Wastes  are  from  the  manufacture  of  sheep,  calf  and 
kid  leather  and  pulled  wools.  Average  analyses  are  given  of  raw  wastes  and 
of  activated  sludge  influents  and  effluents.  A  1,000  gallon  tank  is  operated  on 
the  fill  and  draw  plan  and  the  method  of  building  up  the  activated  sludge  is 
described.  Temperature  of  waste  was  kept  between  65°  and  75°  F.  by  live 
steam.  Aeration  for  11  days  with  20%  sludge,  based  on  2  hours  sedimentation, 
gave  a  stable  effluent  and  reduced  the  ammonia  nitrogen  97%  and  the  albumi- 
noid nitrogen  63%.  Nitrite  and  nitrate  nitrogen  was  increased  in  17  days  from 
0  to  35  parts  per  million.  This  was  mostly  nitrite  and  was  not  changed  to 
nitrate  by  11  days  more  aeration.  Volume  of  sludge  decreased  in  28  days 
from  20  to  7.6%.  When  tank  was  filled  once  a  day  and  air  was  supplied  at 
the  rate  of  0.5  cu.  ft.  per  gallon  per  hour,  the  effluents  were  clear  and  stable. 
Tables  are  given  showing  composition  of  the  sludge  and  the  effects  of  different 
periods  of  sedimentation  on  the  volume  of  the  sludge  and  the  turbidity  of  the 
effluents. 

161  Treatment    of    packing-house    sewage    by    aeration    in    the    presence   of 
activated  sludge.     PAUL  RUDNICK  and  G.  L.  NOBLE.      Jour.  Ind.  Eng. 

Chem.  8,  651-2.  Jour.  Am.  Leather  Chem.  Assoc.  11,  450-3.  Jour.  Soc.  Chem. 
Ind.  35,  904.  Science,  N.  S.  44.  323.  Chem.  Eng.  and  Manuf.  24,  86.  Chem. 
Abst.  10,  3123.  The  sewage  treated  is  a  mixture  of  wastes  from  all  depart- 
ments of  the  packing-house  and  of  domestic  sewage.  It  contains  about  4  times 
as  much  suspended  solids  as  domestic  sewage.  The  tank  is  operated  on  the 
continuous  flow  plan  with  a  10  hour  aeration  using  3  cu.  ft.  of  air  per  gallon 
of  sewage.  The  sludge  is  allowed  to  settle  40  to  60  minutes,  and  the  effluent  is 
clear  and  stable  for  at  least  4  days.  Typical  analyses  of  effluent  give  the 
following  nitrogen  percents: — Albuminoid  2.4  to  7.4,  ammonia  16.2  to  31.2, 
nitrite  0.07  to  0.60,  nitrate  0.  Albuminoid,  ammonia  and  total  organic  nitro- 
gen, total  organic  matter,  and  the  suspended  solids  are  reduced  66  to  95%. 
The  average  analysis  of  the  sludge  on  a  10%  moisture  basis  is  4.59%  nitrogen, 
2%  phosphoric  acid.  No  sludge  drying  method  satisfactory  in  all  respects  has 
been  developed.  Purification  seems  to  be  independent  of  depth  of  aerating 
chamber. 

162  Development  of  the  purification  of  sewage  by  aeration  and  growths  at 
Lawrence,  Mass.    H.  W.  CLARK.    Jour.  Ind.  Eng.  Chem.  8,  653-4.     Jour. 

Soc.  Chem.  Ind.  35,  904.    Science,  N.  S.  44,  322.     Chem.  Abst.  10,  3116.     This 

33 


The  Activated  Sludge  Process 

paper  describes  the  discovery  and  development,  at  the  Lawrence  Experiment 
Station  of  the  Mass.  State  Dept.  of  Health,  of  the  method  of  purifying  sewage 
by  aeration  and  growths,  a  method  quite  generally  known  as  the  activated 
sludge  method.  The  paper  shows  that  the  method  was  developed  there  in 
1911  and  1912,  that  it  was  shown  to  DR.  GILBERT  FOWLER  of  Manchester,  Eng., 
in  the  fall  of  1912,  and  that  the  English  work  was  largely  a  repetition  of  the 
Lawrence  work.  It  quotes  from  FOWLER  and  from  ARDERN  and  LOCKETT,  his 
colleagues,  to  prove  that  their  activated  sludge  work  was  based  upon  the  Law- 
rence work.  The  paper  gives  the  statement  of  DR.  MACLEAN  WILSON  of  Eng- 
land, made  in  his  presidential  address  to  the  Assoc.  of  Sewage  Works  Man- 
agers, to  the  effect  that  the  efficiency  of  growths  in  the  purification  of  sewage 
by  aeration,  was  discovered  at  Lawrence.  The  paper  further  describes  the 
Lawrence  work  during  the  past  4  years  and  gives  the  results  of  much  of  this 
work,  with  the  conclusions  that  the  governing  factors  of  the  success  of  this 
process  of  sewage  treatment  are,  (1)  the  cost  of  power  for  supplying  the 
large  volumes  of  air  necessary;  (2)  a  sewage  that  readily  yields  itself  to  this 
method  of  treatment. 

163  London  sewage  experiments.    NEWS  ITEM.    Eng.  News  76,  37.    Activated 
sludge  experiments  on  London  sewage  are  being  conducted  by  the  County 

Council  of  London,  Eng.,  according  to  the  last  annual  report  of  the  Council. 

164  Sewage  treatment  recommended  for  Lima,  Ohio.    NEWS  ITEM.    Eng.  News 
76,   46.      Riensch-Wurl   screens   and   activated   sludge   tanks   have   been 

recommended  to  treat  the  sewage  of  Lima,  O.,  by  MR.  G.  W.  FULLER.  The  plan 
is  to  operate  the  screens  the  year  round,  but  at  the  outset  to  run  the  activated 
sludge  tanks  about  7  months  in  the  year  when  the  flow  of  the  Ottawa  river  is 
relatively  small. 

165  Purification  of  sewage  and  other  liquids.    W.  JONES  and  JONES  &  ATT- 
WOOD,  L'TD.,   Stourbridge,   Eng.  British   Patent  104,187,  July  11,   1916. 

Jour.  Soc.  Chem.  Ind.  36,  471.  Chem.  Abst.  11,  1868.  In  treating  sewage  and 
other  impure  liquids  by  aeration  in  the  presence  of  bacterial  sludge,  the  sewage 
enters  at  the  end  of  a  long  tank  divided  lengthwise  down  the  middle  and  having 
a  bottom  of  ridge  and  furrow  form,  with  air  diff users  in  the  bottom  of  the 
furrows.  The  flow  is  directed  by  baffles  and  submerged  walls  to  the  opposite 
end,  where  the  sewage  turns  at  right  angles  into  the  other  division  of  the 
tank,  along  which  it  flows  in  the  reverse  direction.  Before  being  discharged 
from  the  tank,  the  sludge  is  deposited  in  settling  chambers  having  bottoms 
sloping  towards  the  dividing  wall  of  the  tank.  At  these  points  part  of  the 
wall  is  cut  away  to  allow  connection  with  the  other  division  of  the  tank.  At 
the  foot  of  the  wall  on  the  first  division  side  is  an  air  diffuser,  and  a  low 
wall  is  built  around  the  diffuser  and  both  sides  of  the  opening  in  the  wall  so 
as  to  form  a  well.  When  the  air  supply  is  turned  on,  an  upward  current  of 
sludge  and  sewage  is  produced  on  that  side  of  the  wall,  and  a  current  of  sludge 
and  sewage  is  induced  to  flow  through  the  opening  from  the  other  side.  In 
this  way  the  sludge  can  be  transferred  from  the  exit  to  the  entry  end  of  the 
tank.  At  intervals  along  the  base  of  the  dividing  wall  there  are  openings 
similar  to  the  foregoing;  in  this  way  sludge  can  be  transferred  from  one  side 
to  the  other  along  the  whole  length  of  the  tank.  In  another  form  of  apparatus, 
instead  of  one  long  tank,  there  are  a  number  of  short  tanks  arranged  side 
by  side  and  connected  in  series;  in  this  form  the  tanks  have  a  flat  bottom  and 
the  air  diffusers  are  placed  at  each  end  of  the  short  tanks. 

166  The  sewage  problem.    SIDNEY  BARWISE.    Surveyor  50,  29-30.    A  history 
of  sewage  filtration,  contact  beds,  etc.     The  activated  sludge  treatment 

is  preferable  if  the  sewage  must  be  pumped.  Mechanical  processes  of  intro- 
ducing air  are  hopeful.  Research  should  be  encouraged. 

167  Activated  sludge  experiments  at  Sheffield.      (Eng.)      DISCUSSION.     Sur- 
veyor 50,  33-4.    In  the  discussion  of  J.  HAWORTH'S  paper  (Ref.  No.  168) 

34 


Abstract  Bibliography — 1916 

C.  H.  BALL  claimed  that  acid  wastes  were  very  detrimental  to  the  process. 
J.  H.  KERSHAW  said  that  sulphocyanides  in  gas  liquors  could  be  eliminated  by 
aeration.  J.  HAWORTH  said  that  a  fungus  growth  had  been  noted  inside  the 
porous  tiles  used  at  Sheffield.  Filtros  plates  were  found  to  give  the  best  air 
distribution. 

168  Experimental  work  with  regard  to  the  purification  of  sewage  by  activated 
sludge.  JOHN  HAWORTH.  Surveyor  50,  40-2.  Can.  Engr.  31,  167-9.  Con- 
tract Record  30,  959-62.  Water  and  Water  Eng.  18,  265-7.  Chem.  Abst.  10, 
3123,  11,  177.  Experiments  at  Sheffield,  Eng.,  extending  over  a  period  of  4 
years  are  reported  in  a  paper  before  the  Assoc.  of  Managers  of  Sewage  Dis- 
posal Works.  Effluents  from  contact  beds  were  subjected  to  (1)  aeration  by 
jets  of  air,  (2)  aeration  through  land  tiles  and  silica  brick,  (3)  aeration  by 
allowing  the  liquid  to  fall  in  sprays,  (4)  aeration  on  percolating  filters  of 
various  depths,  (5)  sand  nitration  and  (6)  precipitation  by  chemicals.  Acti- 
vated sludge  experiments  were  carried  out  on  tank  effluents,  on  mixtures  of 
tank  effluents  and  settled  sewage,  on  settled  sewage  and  on  crude  sewage. 
With  porous  diffusers  well  clarified  effluents  were  usually  obtained  which  were 
within  the  limits  of  allowed  impurity.  Acid  trade  wastes  unless  neutralized, 
temporarily  destroyed  the  activity  of  the  sludge.  Unequal  porosity  caused 
uneven  aeration.  Porous  tiles  became  choked  after  a  few  months  due  to  dust 
and  grease  in  the  compressed  air  and  by  bacterial  growths  in  the  pores  of  the 
plates.  Cracking  of  the  tiles  caused  shut-downs  for  repairs.  An  apparatus 
designed  in  1880  for  the  oxidation  of  oils  gave  satisfactory  results  in  aerating 
sewage.  It  consisted  of  a  vertical  cylindrical  tube  fitted  with  a  spindle  carry- 
ing an  Archimedean  screw  or  propeller  blades  which  sucked  sewage  and  air 
to  the  bottom  of  the  cylinder  upon  being  revolved.  Clarified  npn-putrescible 
effluents  were  obtained  from  settled  sewage  after  5  hours  aeration  in  a  tank 
equipped  with  a  series  of  perforated  steam  pipes  covered  with  2  feet  of  clinker 
broken  into  %  inch  cubes.  Crude  sewage  was  satisfactorily  treated  for  6 
months  in  a  small  iron  tank  equipped  with  a  horizontal  shaft  to  which  were 
attached  hollow  paddles  that  trapped  small  volumes  of  air  when  rotated  above 
the  surface  of  the  contained  sewage.  It  was  concluded  that  (1)  a  normal 
sewage  may  be  clarified  by  the  activated  sludge  method,  (2)  that  mechanical 
circulation  with  minimum  aeration  is  efficient,  (3)  that  trade  wastes  may 
interfere  seriously  with  the  process,  (4)  that  further  investigation  is  needed 
with  respect  to  modes  of  application  of  the  sludge  to  the  sewage,  periodical 
removal  of  the  surplus  sludge  and  the  effect  of  such  removal  on  the  process, 
and  the  costs  of  plant  and  upkeep  before  older  plants  and  methods  can  be 
abandoned,  (5)  that  skilled  control  of  the  process  will  be  essential,  (6)  that, 
while  the  resulting  sludge  is  undoubtedly  richer  in  nitrogenous  organic  matter 
than  ordinary  sewage  sludge,  it  remains  to  be  proved  by  actual  agricultural 
trials  that  such  nitrogen  is  in  a  form  suitable  for  ready  assimilation  by  plant 
life,  and  that  the  sludge  will  be  a  valuable  fertilizer. 

169  Appoint  committee  on  the  activated  sludge  process.     NEWS  ITEM.     Eng. 
Record  74,  91.     At  an  informal  meeting  of  members  of  the  Am.  Soc.  of 

Civil  Eng.  held  at  Pittsburgh  on  June  28,  1916,  F.  A.  DALLYN,  Toronto;  G.  T. 
HAMMOND,  Brooklyn,  and  T.  C.  HATTON,  Milwaukee,  were  appointed  a  com- 
mittee to  prepare  standard  definitions  and  other  terms  relating  to  the  activated 
sludge  process  of  sewage  treatment.  They  will  also  tabulate  and  distribute 
a  summary  of  the  work  now  being  done  or  contemplated,  and  suggest  such 
correlation  of  current  work  as  may  be  desirable.  The  question  of  submitting 
to  the  Commissioner  of  Patents  information  relating  to  priority  of  knowledge 
of  the  activated  sludge  process,  was  left  with  PROF.  EARLE  B.  PHELPS,  H.  W. 
CLARK  and  DR.  EDWARD  BARTOW. 

170  Air  diffuser  experiences  with  activated  sludge  tanks.    ANON.    Eng.  News 
76,  106-10.     Surveyor  50,  160-3.     Chem.  Abst.  10,  2779.     Differences  of 

experiences  and  opinions  as  to  the  use  of  porous  block  and  perforated  pipe 
diffusers  for  intimately  mixing  air  and  agitating  sewage  in  activated  sludge 

35 


The  Activated  Sludge  Process 

tanks  are  expressed  by  engineers  in  charge  of  tests  and  working  plants  at 
Milwaukee  (MR.  HATTON),  Baltimore  (MB.  HENDRICK,  MR.  FRANK),  Brooklyn 
(MR.  HAMMOND),  Cleveland  (MR.  PRATT),  Urbana,  111.,  (DR.  BARTOW),  Chi- 
cago (MR.  PEARSE,  MR.  NOBLE),  and  Houston,  Texas,  (MR.  SANDS).  The 
majority  find  filtros  satisfactory.  Two  prefer  perforated  grids. 

171  Sewage  plans  for  Matawan,  N.  J.     NEWS  ITEM.     Eng.  News  76,  140i 
Plans  for  an  activated  sludge  plant  to  treat  the  sewage  of  Matawan, 

N.  J.,  drawn  by  G.  A.  JOHNSON,  N.  Y.  City,  have  been  approved  by  the  State 
Board  of  Health. 

172  The  activated  sludge  process.     Results  at  Worcester,  Eng.     EDITORIAL. 
Surveyor  50,  83.    JONES  &  ATTWOOD  are  conducting  tests  at  Worcester, 

treating  half  the  flow.  The  tests  are  to  continue  for  one  year  under  agree- 
ment that  750,000  g.  p.  d.  are  to  be  treated  with  an  effluent  containing  not 
more  than  40  p.  p.  m.  of  suspended  solids  and  which  shall  not  be  capable  of 
putrefaction.  Thus  far  five  samples  show  better  than  these  limits. 

173  Tests  show  activated  sludge  process  adapted  to  treatment  of  stock-yards 
wastes.    M.  D.  HARDING,  G.  L.  NOBLE  and  P.  RUDNICK.    Eng.  Record  74, 

137-8.  Chem.  Abst.  10,  3123.  The  sewage  of  ARMOUR  &  Co.,  Chicago,  averages 
700  p.  p.  m.  suspended  matter  and  is  of  a  complex  nature.  Using  15%  by 
volume  of  activated  sludge  with  beef-slaughtering  sewage,  a  stable  effluent 
was  obtained  after  two  days  aeration;  long  before  clarification.  Experiments 
are  being  conducted  in  a  30,000  gallon  tank  on  the  continuous  flow  plan,  the 
air  being  distributed  by  means  of  one  inch  galvanized-iron  pipes,  perforated 
with  one-twenty-fifth  inch  holes  spaced  two  inches  apart.  Processes  for  de- 
watering  the  sludge  are  being  studied.  The  estimated  cost  of  treatment  per 
million  gallons  of  sewage  is  $3,  exclusive  of  interest,  depreciation  and  repairs. 

174  Progress  in  the  treatment  of  sewage.    EDITORIAL.    Surveyor  50,  93.    Com- 
ment on  the  article  of  S.  BARWISE,  (Ref.  No.  166)   and  reference  to  J. 

HAWORTH'S  method  of  mechanical  agitation  at  Worcester.  Expresses  the 
belief  that  further  investigations  should  be  directed  along  this  line. 

175  Stockyard  wastes  can  be  treated  by  activated  sludge  process.     ANON. 
Contract  Record  30,  788-90.    Digest  of  the  article  by  HARDING,  NOBLE  and 

RUDNICK  appearing  in  the  Eng.  Record.     (Cf.  Ref.  No.  173.) 

176  Baltimore  activated  sludge  air  diffusers.    L.  C.  FRANK.    Eng.  News  76, 
267.     Chem.  Abst.  10,  3123.     It  was  found  that  some  of  the  old  filtros 

disks  showed  evidence  of  disintegration  upon  removal  from  the  umbrella- 
shaped  diffuser  grid. 

177  Apparatus  for  introducing  gases  into  intimate  contact  with  liquid  sewage. 

G.  W.  MOTTRAM,  Deepcar,  near  Sheffield,  Eng.  U.  S.  Patent  1,195,067, 
Aug.  15,  1916.  (Application  filed  Feb.  17,  1916.  3  claims.)  Off.  Gaz.  229, 
872.  Chem.  Abst.  10,  2493.  Claim  3: — The  combination,  with  a  tank  of  sew- 
age, of  a  vertical  air  supply  pipe  provided  with  laterally  projecting  branch 
pipes  arranged  in  the  lower  part  of  the  tank  and  provided  with  outlet  holes, 
tubular  casings  of  porous  material  through  which  air  can  pass  inclosing  the 
said  branch  pipes,  and  means  for  revolving  same.  (Cf.  British  pat.  2,421. 
Ref.  No.  34.) 

178  Activated  sludge  progress.    EDITORIAL.    Eng.  News  76,  366.     Refers  to 
several  plants   in   the   United    States   and    England,   cites   the   need   of 

caution  in  adopting  the  method  because  of  the  many  details  yet  to  be  worked 
put,  and  suggests  that  engineers  should  give  it  careful  consideration  because 
it  would  fall  little  short  of  revolutionizing  sewage  disposal  should  its  highest 
promises  be  realized. 


Abstract  Bibliography — 1916 

179  Activated  sludge  plant  for  Hermosa  Beach,  Calif.     NEWS  ITEM.     Eng. 
News  76,  380.    Munic.  Engr.  51,  105.     The  first  Pacific  coast  city  to  pro- 
ject an  activated  sludge  plant  has  authorized  the  construction  of  a  "BROSIUS 
system  of  activated  and  aerated  sludge  treatment."     The  plant  will  consist 
of  8  concrete  tanks  each  12.5  ft.  in  diameter  by  13  ft.  deep. 

180  Activated  sludge  treatment  in  America.    ANON.   Engineer  122,  170.    Re- 
fers to  the  Milwaukee  plant  and  the  recent  papers  by  T.  C.  HATTON;  the 

Baltimore  and  Brooklyn  experimental  plants,  and  to  G.  T.  HAMMOND'S  recent 
investigation  of  the  subject.  This  article  deals  especially  with  the  various  air 
diffusing  means  employed,  filtros  being  fully  described. 

181  Apparatus  for  aerating  sewage.    GRIFFITHS  and  HARTLEY.    British  Pat- 
ent Application  No.  12,084,  Aug.  26,  1916.     Jour.  Soc.  Chem.  Ind.  35, 

Suppl.  55. 

182  How  other  cities  in  the  United  States  are  disposing  of  their  sewage. 

R.  V.  ORBISON  and  T.  D.  ALLIN.  Pamphlet  (Sept.  1916)  Proc.  19th 
Ann.  Conv.  Pacific  Munic.  61-77.  The  activated  sludge  process  referred  to 
as  in  Ref.  No's.  210,  223  and  250. 

183  The  activated  sludge  process.     An  American  Committee.     ANON.     Sur- 
veyor 50,  247.     On  Sept.  15,  1916,  members  of  the  Am.  Soc.  C.  E.  met 

at  Pittsburgh  and  appointed  F.  A.  DALLYN,  G.  T.  HAMMOND  and  T.  C.  HATTON 
a  committee  to  prepare  standard  definitions  of  the  activated  sludge  process 
and  to  tabulate  and  distribute  a  summary  of  the  work  in  progress.  A  pat- 
ent committee  was  also  appointed  consisting  of  E.  B.  PHELPS,  H.  W.  CLARK 
and  DR.  E.  BARTOW  to  present  evidence  of  priority  of  knowledge  of  the 
activated  sludge  process  to  the  Commissioner  of  Patents. 

184  Activated  sludge  in  India.    NEWS  ITEM.    Eng.  News  76,  624.    Activated 
sludge   studies   at   three   points   in   India,   with   particular   attention  to 

fertilizer  possibiltes,  are  to  be  made  by  DR.  G.  J.  FOWLER,  formerly  of  Man- 
chester, Eng. 

185  Present  status  of  activated  sludge.    EDITORIAL.    Munic.  Jour.  41,  383-4. 
Chem.  Abst.  10,  3122.     The  editor  indicates  that  the  process  is  still  in 

the  experimental  stage  and  that  the  cost  of  handling  the  sludge  is  very 
uncertain. 

186  Bacteriological  study  of  sewage  purification  by  aeration.     R.  RUSSEL  and 
DR.  E.  BARTOW.     Univ.  Ill  Bull.  14,  348-58.     (Water  Survey  Series  No. 

13)  Chem.  Abst.  11,  1707.  Expt.  Sta.  Record  38,  490.  The  investigation  has 
shown  the  following  bacteriological  features  of  the  activated  sludge  process 
of  sewage  purification:  (1)  There  is  a  large  and  consistent  reduction  of  the 
total  number  of  bacteria  in  the  sewage;  (2)  the  actual  stabilization  process 
is  due  to  a  typical  aerobic  bacterial  flora  which  gains  almost  complete  ascend- 
ency, the  other  inhabitants  being  largely  incidental;  (3)  the  actual  nitrifi- 
cation is  accomplished  by  two  typical  known  nitrifiers  "Nitrosomonas"  and 
"Nitrobacter." 

187  Nitrogen  in  activated  sludge.     EDITORIAL.    Eng.  News  76,  663.     Refers 
to  a  paper  by  MR.  COPELAND  (Ref.  No.  188)   and  the  difficulties  of  de- 
watering  activated  sludge.     "If  a  process  of  sewage  disposal  could  be  per- 
fected that  would  yield  a  sludge  convertible  into  fertilizing  material  at  less 
than  capital  charges  and  operating  expenses,  and  without  causing  a  nuisance, 
one  of  the  most  baffling  municipal  problems  of  the  last  half  century  would 
be  solved." 

188  Nitrogen  from  sewage  sludge,  plain  and  activated.     W.  R.   COPELAND. 
Eng.  News  76,  665-6.    Can.  Engr.  31,  340.    Munic.  Jour.  41,  446.    Chem. 

Abst.  10,  3124;  11,  509.    The  practicability  of  recovering  nitrogen  from  sewage 

37 


The  Activated  Sludge  Process 

depends  upon  (1)  the  amount  present,  (2)  the  cost  of  recovering  and  dis- 
posing of  it,  and  (3)  its  market  value.  Nitrogen  is  largely  recovered  from 
suspended  matter.  Sludge  from  best  known  processes  ranges  from  1.2  to  3% 
nitrogen,  whereas  activated  sludge  at  Milwaukee  contains  5  to  9%  wet,  and 
4  to  4.5%  when  dry.  Estimated  cost  of  recovery  is  $10  to  $12  per  ton  with 
10%  moisture,  with  market  value  from  $9  to  $15. 

189  Discussion  of  Mr.  Gopeland's  paper  on  nitrogen  recovery.   G.  W.  FULLER. 
Eng.  News  76,  667.    Eng.  Record  74,  445.    Chem.  Abst,  11,  80.    Mr.  Fuller 

points  out  that  while  the  activated  sludge  process  saves  loss  of  nitrogen,  the 
real  problem  is  to  economically  dewater  the  sludge.  Possible  use  of  the 
DICKSON  yeast  fermentation  process  is  suggested,  with  the  final  reduction 
of  water  content  by  means  of  heat  dryers. 

190  Commercial  possibilities  with  activated  sludge.    EDITORIAL.     Eng.  Record 
74,  428.     Commenting  on  MR.   COPELAND'S  paper   (Ref.   No.  191)    it  is 

the  opinion  that  if  sewage  treatment  plants  can  produce  valuable  fertilizer 
material,  their  usefulness  will  increase,  and  the  reduced  operating  costs  will 
also  stimulate  plant  construction,  especially  where  present  sewage  disposal 
methods  create  a  nuisance. 

191  Nitrogen  recovery  from  sewage  sludge  reaches  a  commercially  practicable 
stage.    W.  R.  COPELAND.    Eng.  Record  74,  444-5.     Chem.  Abst.  11,  273. 

Parallel  experiments  on  Milwaukee  sewage  showed  that  most  of  the  nitrogen 
in  the  sewage  passed  out  in  the  suspended  and  colloidal  matters  in  the 
effluent  when  treated  by  the  Imhoff  tank,  but  in  the  activated  sludge  method 
it  was  stored  up  in  the  sludge.  As  secured  in  the  settling  tank  activated 
sludge  contained  98-9%  of  water  which  has  been  difficult  to  remove.  Latest 
information  favors  a  combination  of  settling  and  decantation  to  reduce  to 
96%,  filter-pressing  to  bring  down  to  75%,  and  dewatering  of  the  press-cake 
in  a  drier  to  10%  or  less.  Lime  in  filter-pressing  was  shown  to  be  unnecessary. 
Little  or  no  nitrogen  was  lost  in  drying.  Data  indicates  that  Milwaukee  sew- 
age will  contain  4.6  to  5%  nitrogen  as  ammonia,  0.6  to  0.7%  available  phos- 
phoric acid,  0.25  to  0.50%  potash  and  3  to  4%  fat.  Tables  give  analyses  of 
sewage  and  of  effluents  and  sludges  obtained  by  both  Imhoff  and  activated 
sludge  processes. 

192  Aeration  suggested  for  sludge  disposal.    G.  T.  HAMMOND.     Eng.  Record 
74,   448-9.     Surveyor  50,   400-1.      Chem.  Abst.    11,   375.      Two  to   four 

thousand  gallons  of  sludge  containing  96  to  99%  of  water  result  from  each 
million  gallons  of  sewage  treated  by  the  activated  sludge  process.  Many 
cities  would  not  install  expensive  dewatering  plants,  and  for  these  fine 
screening,  partial  drying  by  pressing  or  prolonged  aeration  of  the  sludge 
offer  possibilities  for  minimization  of  the  amount  of  sludge  produced.  Long 
contnued  aeration  reduces  activated  sludge  to  10%  or  less  of  its  original 
volume.  Experimentation  would  be  necessary  to  produce  properly  designed 
plants  for  removing  excess  water  as  the  cost  of  aerating  large  volumes  would 
be  prohibitive. 

193  Large  activated  sludge  plant  at  Milwaukee,  Wis.    ANON.     Eng.  News  76 
686-8.     Chem.  Abst.  11,  510.     A  two  million  gallon  daily  capacity  plant 

costing  $61,536  is  described.  Operating  data  is  given.  Steeper  slopes  of 
60  degrees  from  the  horizontal  are  recommended  for  hopper  of  settling  tank. 
Air  pressure  required  is  increasing  with  use,  and  larger  amounts  in  cold 
weather.  Immediate  settling  following  aeration  is  necessary,  with  constant 
removal  of  the  sludge. 

194  Apparatus  for  aerating  sewage  and  other  foul  liquids.     R.  AMES,  Brigh- 
ton, Eng.     British  Patent  110,197,  Oct.  13,  1916.      (Addition  to  British 

Patent  104,361.  Ref.  No.  127).  Jour.  Soc.  Chem.  Ind.  36,  1247.  The  original 
apparatus  is  improved  by  providing  above  the  tank  a  rotary  chamber,  to 

38 


A bstract  Bibliography — 1 91 6 

which  the  incoming  sewage  is  supplied.  From  this  chamber  the  sewage  flows 
into  troughs,  fixed  to  the  chamber  on  either  side,  from  which  depend  open- 
topped  vertical  pipes  with  bell-mouth  bottoms  reaching  to  within  a  few 
inches  of  the  bottom  of  the  tank.  The  compressed  air  supply  comes  from 
an  air  chamber  on  the  top  of  the  sewage  chamber,  the  air  being  conveyed 
by  pipes  which  pass  down  the  inside  of  the  vertical  sewage  pipes  and  end 
in  atomizers  located  in  the  bell-mouths  of  the  sewage  pipes. 

195  Sewage  treatment  by  aeration  and  activation.     G.  T.  HAMMOND.     Can. 
Engr.  31,  305-11.     Surveyor  50,  453-5;  479-80.     Proc.  Am.  Soc.  Munic. 

Impvts.  23,  327-403.  Chem.  Abst.  11,  1867.  (Also  in  pamphlet  form,  reprinted 
from  the  Proc.  Am.  Soc.  Munic.  Impvts.,  1916,  with  discussion  of  all  activated 
sludge  papers  presented  at  that  meeting,  pp.  101).  A  very  complete  and 
critical  review  of  the  activated  sludge  process.  Refers  to  sewage  aeration 
experiments  from  1884  to  the  present  time,  and  as  a  result  of  personal  visits 
to  the  several  plants,  or  by  correspondence  with  those  in  charge,  the  author 
has  collected  in  this  article  all  the  important  data  of  the  plants  at  Balti- 
more, Brooklyn,  Champaign,  111.,  Chicago,  (Armour  and  Sanit.  Dist.  plants) 
Cleveland,  Edmonton,  Can.,  Fort  Worth,  Tex.,  (Armour  plant),  Houston, 
Tex.,  Lawrence,  Mass.,  Milwaukee,  Regina,  Can.,  San  Marcos,  Tex.,  and 
Urbana,  111.  No  forecast  of  the  value  of  the  activated  sludge  process  can  be 
made  at  this  time,  but  it  is  noted  that  methods  of  air  distribution  and  sludge 
treatment  still  require  study.  The  apparent  advantages  are  a  clear  and 
stable  effluent  from  a  plant  requiring  small  area,  and  freedom  from  odor. 

196  Activated   sludge   sewage   treatment.     ANON.     Munic.   Jour.   41,   480-3; 
510-13.     A  review  of  the  experiments  being  conducted  and  results  ob- 
tained at  11  plants,  with  an  outline  of  the  provisions  for  co-operation  of  ex- 
perimenters.     Abstracts   of    several   papers   presented    at   the    1916   meeting 
Am.  Soc.  Munic.  Impvts. 

197  Present  status  of  activated  sludge.     ANON.     Water  and  Water  Eng.  18, 
257-8.     Chem.  Abst.  11,  178.     While  the  activated  sludge  process  has 

been  more  thoroughly  and  promptly  investigated  than  any  other  method  of 
sewage  disposal,  yet  the  plant  at  San  Marcos,  Texas,  treating  about  150,000 
gallons  of  sewage  per  day,  is  the  only  plant  in  actual  operation  and  not 
under  experimental  conditions.  The  work  at  Milwaukee  is  reviewed.  Engi- 
neers are  cautioned  against  hasty  copying  of  experimental  plants. 

198  The  activated   sludge   process.     EDITORIAL.     Surveyor  50,  373-4.     Com- 
ment on  the  interesting  results  at  Manchester,  Eng.     Experiments  on 

sedimentation  are  needed.  The  process  can  be  adjusted  to  the  character  of 
the  sewage  and  the  quality  of  effluent  desired.  Desirable  to  purify  to  a 
greater  degree  when  stream  flow  is  at  a  minimum,  and  to  vary  air  supply 
accordingly. 

199  The  activated  sludge  process.     Manchester  research  work.    ANON.     Sur- 
veyor 50,  379-80.     Chem.  Abst.  11,  2517.     A  digest  of  the  annual  report 

of  the  Manchester  Rivers  Committee.  With  a  weak  domestic  sewage  tried 
at  the  Withington  works,  satisfactory  purification  was  not  dependent  on  the 
stage  to  which  nitrification  was  carried,  nor  was  the  question  of  temperature 
as  serious  as  with  sewage  containing  trade  wastes,  satisfactory  purification 
being  maintained  with  air  temperatures  below  zero,  and  sewage  tempera- 
tures from  5  to  10. 

200  Some  remarks  on  activated  sludge.    W.  T.  CARPENTER  and  M.  P.  HORO- 
WITZ.   Am.  Jour.  Public  Health  6,  1218-23.     Chem.  Abst.  11,  1224.     An 

aerated  contact  bed  was  fitted  up  in  a  50  gallon  barrel.  After  5  hours  aera- 
tion the  liquid  drawn  from  the  barrel  was  practically  devoid  of  suspended 
matter  and  purified.  Purification  was  complete  after  20  hours.  A  table  of 
results  is  given  from  which  it  is  seen  that  the  rate  of  fall  of  demand  for 

39 


The  Activated  Sludge  Process 

oxygen  diminishes  throughout  the  cycle,  thus  showing  that  the  action  pro- 
ceeds rapidly  at  first  and  that  a  definite  amount  of  air  would  be  most 
advantageously  used  by  blowing  it  rapidly  in  the  beginning  and  more  slowly 
later.  It  is  claimed  that  while  a  short  period  of  retention  will  suffice  to 
settle  the  sludge  which  has  been  aerated  20  hours  without  any  addition  of 
fresh  sewage,  a  longer  period  is  necessary  when  operation  is  continuous 
during  a  shorter  aeration  period.  Short-circuiting  the  sewage  can  be  mini- 
mized by  dividing  the  retention  among  several  smaller  tanks  in  series  or  by 
using  one  tank  with  a  length  great  in  proportion  to  its  breadth  and  height. 

201  Mechanical   agitation  of   sewage   proved   unsuccessful.     C.   H.   NORDELL, 
Eng.  News  76,  856.     Chem.  Abst.  11,  509.     Description  of  some  experi- 
ments made  with  screw  propellers  and  stirrers  of  various  forms,  from  which 
evidence  is  deduced  that  agitation  itself  plays  a  minor  part,   liberal  aera- 
tion being  essential  for  the  efficient  and  economical  working  of  the  activated 
sludge  process. 

202  Definitions  of  sewerage  and  sewage  disposal  terms.    ANON.     Eng.  News 
76,  858.    Am.  Jour.  Public  Health  7,  847.     The  committee  on  the  sewer- 
age and  sewage  disposal  of  the  sanitary  section  of  the  Am.  Public   Health 
Assoc.,  with  the  co-operation  of  eminent  engineers,  suggests  the  following  def- 
inition for  the  activated  sludge  process: — "Activated-Sludge  Process  consists  in 
the  agitation  of  a  mixture  of  sewage  with  about  15%  or  more  of  its  volume  of 
bacterially  active  liquid  sludge  in  the  presence  of  ample  atmospheric  oxygen, 
for  a  sufficient  period  of  time  to  at  least  coagulate  a  large  proportion  of  the 
collodial  substances,  followed  by  sedimentation  adequate  for  the   subsidence 
of  the  sludge  flocculi;  the  activated  sludge  having  been  previously  produced 
by  aeration  of  successive  portions  of   sewage   and  maintained   in   its   active 
condition  by  adequate  aeration  by  itself  or  in  contact  with  sewage." 

203  Digestion  of   activated   sludge.     H.   P.   EDDY.     Proc.   Am.   Soc.  Munic. 
Impvts.  23,  429-39.     Can.  Engr.  31,  353-5.     Surveyor  50,  504-6.     Details 

are  given  of  the  operation  of  an  experimental  activated  sludge  plant  on  tan- 
nery wastes,  including  analytical  data,  sludge  accumulation  period,  sludge  ac- 
tivation period,  period  of  operation  on  one  filling  per  day,  with  increased 
proportion  of  sludge,  on  two  fillings  per  day,  with  and  without  sludge  re- 
moval, quantity  of  sludge  produced,  sludge  digestion,  digestion  of  fats,  in- 
creasing the  volume  of  sludge  by  its  partial  removal.  About  10  cu.  ft.  of 
air  per  gallon  of  sewage  were  used  with  12  hours  aeration  on  the  fill  and 
draw  plan.  Sludge  volume  will  not  exceed  10,000  gallons  per  million  gallons 
of  sewage.  88.7%  of  the  fats  were  digested  and  the  mineral  matter  in  the 
sludge  decreased  77.8%. 

204  Comparative  costs  of  construction  and  operation  of  the  activated  sludge 
and  Imhoff  trickling-filter  process  of  sewage  treatment.     ANON.     Eng. 

Record  74,  557.  Eng.  &  Contg.  47,  154-7.  From  a  paper  by  H.  P.  EDDY  pre- 
sented to  the  West.  Soc.  of  Engs.,  covering  an  engineering  study  of  the  two 
processes  based  on  comparative  designs  for  Fitchburg,  Mass.,  in  which  the 
total  estimated  cost  of  the  Imhoff  plant  is  $431,170  and  of  the  activated 
sludge  plant  $313,880,  engineering  and  administration  charges  included.  Both 
plants  designed  for  5.5  million  gallons  daily  capacity.  Estimated  annual  costs 
are  $17,080  for  the  Imhoff  and  $40,140  for  the  activated  sludge.  Advantages 
and  disadvantages  of  both  methods  are  discussed.  (Cf.  Ref.  No.  217). 

205  The  pioneer  activated  sludge  plant.    ANON.     Contract  Record  30,  1066-8. 
A  description  of  the  new  1,600,000  g.  p.  d.  installation  at  Milwaukee, 

(Ref.  No.  70)  covering  the  general  scheme,  air  diffuser  experiments,  and 
some  results  of  operation. 

206  Disposal  of  sludge  from  activated  process.    ANON.     Contract  Record  30, 
1074.     Review  of  a  paper  by  G.  T.   HAMMOND  in  which  the  work  of 

40 


Abstract  Bibliography — 1916 

FOWLER  and  others,  and  the  experiments  at  Brooklyn,  Lawrence,  Milwaukee 
and  ARMOUR  &  Co.,  Chicago,  are  referred  to.  The  SCHAEFER-TER-MEER  centri- 
fugal sludge  drier,  the  WORTHINGTON  press  and  the  DICKSON  yeast  process 
are  considered  in  connection  with  sludge  dewatering.  The  long  continued 
aeration  of  the  sludge  is  also  suggested  as  a  means  of  minimizing  the 
surplus  sludge. 

207  Results  and  conclusions  from  a  year's  operation  of  the  activated  sludge 
sewage  treatment  plant  at  Milwaukee.    ANON.     Eng.  &  Contg.  46,  407-9. 

Chem.  Abst.  11,  510.  Expt.  Sta.  Record  36,  489.  Digest  of  a  paper  by  T.  C. 
HATTON  before  the  Am.  Soc.  Munic.  Impvts.,  1916  meeting,  covering  work 
more  fully  described  in  the  annual  report  of  the  testing  station.  (Cf.  Ref. 
No.  227). 

208  Activated  sludge  novelties  at  Hermosa  Beach,  Calif.     A.  M.   BROSIUS. 
Eng.  News  76,  890-2.     Chem.  Abst.  11,  510.     This  plant  handles  400,000 

gallons  of  sewage  per  day  with  an  aeration  period  of  3  hours.  60  kw.  hours 
are  required  per  100,000  gallons  treated.  A  submerged  propeller  or  dif- 
fuser  wheel  in  the  bottom  of  a  circular  tank  draws  air  and  sewage  down 
through  a  central  foam  chamber  to  the  bottom  of  the  tank,  from  which  both 
pass  upwards.  Air  under  one  pound  pressure  will  also  be  admitted  to  each 
central  pipe. 

209  Terms  used  in  sewerage  and  sewage  disposal.    An  American  Committee's 
definitions.     ANON.     Surveyor  50,   430-2.     From   a  report  of  the  com- 
mittee of  the  Am.  Pub.  Health  Assoc.,  referring  to  activated  sludge  as   in 
Ref.  No.  202. 

210  Activated  sludge  given  preference.     T.  D.  ALLIN  and  R.  V.   ORBISON. 
Eng.  Record  74,  628.     Chem.  Abst.  11,  375.     After  visiting  several  sew- 
age   treatment    plants    throughout   this    country    in    behalf    of    the    city   t)f 
Pasadena,   Calif.,   the   committee   reports   that   the   activated   sludge   process 
occupies  less  space,  costs  less  for  construction,  gives  a  better  effluent  and  is 
absolutely   odorless,   as   compared   to    Imhoff   tank   and   the    sprinkling   filter 
process.     The  cost  of  operation  is  higher  but  the  greater  fertilizing  value  of 
activated  sludge  will  reduce  the  difference.     (Cf.  Ref.  Nos.  182,  223,  and  250). 

211  Activated  sludge  experiments  at  the  University  of  Illinois.     E.  BARTOW, 
F.  W.  MOHLMAN  and  J.  F.  SCHNELLBACH.    Eng.  News  76,  972-3.    Sur- 
veyor 51,  6.    Am.  Jour.  Public  Health  7,  679.    Chem.  Abst.  11,  509.    The  plant 
handles  about  150,000  gallons  daily  of  domestic  sewage,  using  2  cu.  ft.  of  air 
per  gallon.     Stable  effluents  have  usually  been  obtained.     The  settling  cham- 
ber— 24  to  37  minute  period — has  proved  too  small. 

212  Recommends  isolated  sewage  treatment  plants  for  lake  cities  north  of 
Chicago.    J.  W.  ALVORD,  H.  P.  EDDY  and  G.  W.  FULLER.     Eng.  Record  74, 

656-8.  Chem.  Abst.  11,  679.  The  activated  sludge  process  is  too  expensive 
for  local  conditions. 

213  Bottom  of  pipe  perforated  for  air  distribution.    ANON.     Eng.  Record  74, 
660.     Air  distribution  in  the  activated  sludge  plant  at  Edmonton,  Can., 

is  accomplished  by  pipes  perforated  on  the  under  side  with  %-inch  holes,  3- 
inch  centers.  Provision  is  made  for  lifting  each  air  line  independently. 

214  Chicago  sewage  treatment  and  dilution.     NEWS  ITEM.     Eng.  News  76, 
1056.    Eng.  Record  74,  695.    Munic.  Jour.  41,  677.     Chem.  Abst.  11,  510. 

Among  the  important  improvements  in  the  sewage  disposal  system  of  Chicago, 
there  is  a  recommendation  by  the  Board  of  Trustees  of  the  Sanitary  District 
for  the  treatment  of  domestic  sewage  centering  at  the  39th  street  pumping 
station — from  an  area  of  about  22  square  miles — by  settling  basins  or  an 
activated  sludge  plant  in  the  vicinity  of  this  station. 

41 


The  Activated  Sludge  Process 

215  Mechanical   agitation   and   aeration   and   trade   wastes   in   the   activated 
sludge  process.     ANON.     Munic.  Eng'rg.  51,  234-5.     From  a  paper  by 

JOHN  HAWORTH  presented  at  a  meeting  of  the  Assoc.  of  Mgrs.  of  Sewage 
Disposal  Works  held  at  Sheffield,  Eng.,  dealing  with  the  activated  sludge 
work  in  that  city.  (Cf.  Ref.  No.  168). 

216  A  new  type  of  trickling  filter.    G.  G.  NASMITH.     Jour.  Royal  Sanit.  Inst. 

37,  (Dec.  1916).  Surveyor  51,  4-5.  Expt.  Sta.  Record  37,  488.  The 
author  states  that  the  principles  of  the  trickling  filter  and  the  activated 
sludge  process  are  identical.  In  the  first,  the  sewage  trickles  over  the  bac- 
terial mass  in  the  air;  in  the  activated  sludge  process  air  is  passed  into  the 
sewage  in  contact  with  the  bacterial  mass;  the  end  results  being  exactly  the 
same. 

217  A   comparison  of   the   activated   sludge   and   the   Imhoff   tank-trickling; 
filter  processes  of  sewage  treatment.      H.   P.   EDDY.     Jour.   West.  Soc. 

Engs.  21,  816-52.  Engineering  104,  288-90,  319-20.  Surveyor  51,  370-2.  Expt. 
Sta.  Record  37,  694.  A  detailed  specific  comparison  of  the  two  methods  from 
which  the  author  concludes  that,  "At  the  present  time  it  appears  that  the 
Imhoff  tank-trickling  filter  process  is  a  less  expensive  means  of  oxidizing  the 
organic  matter  of  sewage  and  industrial  wastes  than  the  activated  sludge 
process,  where  oxidation  alone  is  considered.  If  the  areas  of  land  required 
for  isolation,  the  loss  of  head  in  the  plant,  the  danger  of  objectionable  odors 
and  of  fly  annoyance,  and  other  disadvantages  of  the  trickling  filter  process 
are  of  marked  importance  in  any  specific  case,  the  balance  may  be  decidedly 
in  favor  of  the  activated  sludge  process,  even  in  its  present  state  of  develop- 
ment." Comparative  cost  estimates  are  included.  (Cf.  Ref.  No.  204). 

218  Recovery   of   fats   and   nitrogen   compounds   from   sewage.     S.    RIDEAL. 

Chem.  Trade  Jour.  59,  571-2.  Jour.  Soc.  Chem.  Ind.  36,  44.  Can.  Engr. 
32,  82,  157.  Chem.  Abst.  11,  859,  1225.  Expt.  Sta.  Record  38,  625.  Dried 
active  sludge  with  10%  moisture,  contains  5  to  9%  N  and  if  retorted  should 
give  higher  yields  of  ammoniaca!  liquor  than  are  obtained  from  coal  in  gas 
works.  To  recover  nitrates  from  effluents  it  is  suggested  that  a  filter  bed 
with  no  effluent  drain,  protected  from  rainfall,  might  be  irrigated  with  the 
effluent  so  that  nitrates  would  become  gradually  concentrated  by  evaporation. 
"If  all  the  nitrogen  in  sewage  could  be  recovered,  it  is  estimated  that  the 
military  camps  would  yield  11,640  tons  and  the  civil  population  116,400  tons 
per  annum." 

219  Activated  sludge  results  at  Cleveland.    R.  W.  PRATT  and  G.  B.  GASCOIGNE. 
Eng.  News  76,  1061-6,  1124-8.     Chem.  Abst.   11,   509.     The  conditions 

require  only  a  low  degree  of  purification  for  the  sewage  from  75%  of  the 
population.  To  remove  iron  from  the  sewage  requires  %  hour  more  aera- 
tion than  clarification.  The  sewage  treated  contains  in  parts  per  million: — 
Suspended  matter  250,  organic  nitrogen  8.5,  free  ammonia  12.1,  iron  21, 
occasionally  up  to  350.  Filtros  plates  were  used  for  air  distribution,  in 
ratio  of  plate  surface  to  tank  area,  1  to  5.  Some  clogging  has  been  noted. 
The  tanks  are  15  feet  1  inch  deep,  requiring  0.75  cu.  ft.  free  air  per  gallon 
of  sewage  for  clarification.  With  equal  aeration  for  liquid  and  solid,  a  3 
hour  period  is  required.  In  the  horizontal  flow  settling  basin  a  30  minute 
period  is  ample  with  a  velocity  of  1  foot  per  minute.  Steep  bottom  slopes 
are  required.  25%  of  the  sewage  treated  is  pumped  back.  Very  careful 
operation  is  required.  Minimum  cost  for  labor  and  power  per  million  gallons 
is  $4.50  with  power  at  0.75  cent  per  kw.  hour.  Analytical  results  are  given. 
Re-aeration  of  the  sludge  with  20  to  25  cu.  ft.  of  air  per  gallon  improves  its 
drying  and  keeping  qualities.  Separate  sludge  digestion  is  possible.  Unless 
the  unit  quantities  of  sludge  produced  are  materally  lessened,  the  use  of 
sand  beds  for  dewatering  is  financially  prohibitive.  Centrifugals  have  re- 
duced sludge  moisture  to  85%.  Available  data  indicate  that  presses  are  suit- 
able for  primary  dewatering,  irrespective  of  whether  or  not  the  sludge  war- 

42 


Abstract  Bibliography — 1916 

rants  further  drying  for  fertilizers.  Present  data  are  insufficient  to  estimate 
the  cost  of  sludge  disposal.  The  nitrogen  value  in  Cleveland  sludge  may 
be  about  $5.50  per  million  gallons  of  sewage. 

220  The  attractiveness  of  the  activated  sludge  process  to  sanitary  engineers. 
EDITORIAL.     Can.  Engr.  31,   475.     "Probably  there  has  never  been  an 

innovation  which  ever  took  so  firm  a  hold  of  sanitary  engineers  and  has 
engaged  the  attention  of  so  many  students  of  sewage  disposal  as  the  acti- 
vated sludge  process.  A  surprisingly  large  number  of  municipalities  and 
industrial  plants  throughout  the  continent  are  either  conducting  experimental 
plants  or  are  laying  plans  to  do  so.  Out  of  all  this  the  science  of  sanitary 
engineering  should  emerge  the  richer." 

221  Tanks  for  the  purification  of  sewage.     G.  W.  and  J.  F.  NAYLOR,  Denby 
Dale,  Yorks,  Eng.  British  Patent  111,548,  Dec.  7,  1916.    Jour.  Soc.  Chem. 

Ind.  37,  72A.  The  air  diffusing  means  along  the  bottom  of  the  tank  for  the 
treatment  of  sewage  by  diffusion  of  air  in  small  bubbles,  may  consist  of  non- 
porous  tubes  with  small  perforations  on  their  under  side,  covered  by  strips 
of  cloth  tightly  encircling  the  tubes.  The  whole  length  of  the  tube  is  en- 
closed by  a  cloth  casing  kept  from  touching  the  under  side  of  the  tube  by  de- 
pending stays.  The  air  from  the  perforations  in  the  tube  diffuses  through 
the  cloth  casing,  mainly  at  the  sides.  The  tubes  may  also  be  made  of  porous 
earthenware,  the  upper  surfaces  being  painted  over  so  that  air  escapes  from 
the  sides  only. 

222  Purification  of  sewage  and  other  impure  liquids.    W.  JONES,  Stourbridge, 
and  JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Eng.     British  Patent  111,720, 

Dec.  9,  1916.  Jour.  Soc.  Chem.  Ind.  37,  72 A.  Chem.  Abst.  12,  597.  Crude 
sewage  enters  a  treatment  tank  through  a  hydropneumatic  appliance  whereby 
a  mixture  of  sewage  and  air  is  delivered  well  below  the  surface  into  the  body 
of  the  liquid  in  the  tank.  The  bottom  of  the  tank  is  of  inverted  conical  shape 
with  a  sump  at  the  apex,  and  the  dilute  sludge  passes  out  by  the  sump  into 
a  separate  tank  with  ridged  bottom  provided  with  air  diffusers,  whereby  it  is 
aerated  and  circulated.  This  invigorated  sludge  is  then  returned  by  an  air 
lift  to  the  top  of  the  liquid  in  the  sewage  tank.  In  another  form  of  the  tank, 
the  mixture  of  sewage  and  air  is  delivered  into  radial  arms  at  the  level  of 
the  conical  portion  of  the  tank,  and  as  it  issues  from  these  through  a  series 
of  holes  along  one  side,  it  causes  them  to  revolve  and  bring  about  a  perfect 
distribution.  The  process  may  be  carried  out  also  in  several  tanks  connected 
in  series. 

223  Sewage  disposal  methods  of  16  cities.    ANON.    Eng.  &  Contg.  46,  534-6. 
Pacific  Municipalities,   March,  1917.     From   a  report  by  T.   D.   ALLIN 

and  R.  V.  ORBISON  referring  to  the  activated  sludge  plants  at  Baltimore, 
Chicago,  Cleveland,  Milwaukee,  and  the  contemplated  plant  at  Worcester, 
Mass.  (Cf.  Ref.  Nos.  182,  210  and  250). 

224  Activated  sludge  process.     ANON.     Can.  Engr.  31,  489-90.     Ann.  Report 
Manchester  Rivers  Com.  (1916)     Experiment  has  demonstrated  that  the 

air  supply  should  be  filtered  and  the  sewage  screened  from  detritus.  Abnor- 
mal amounts  of  trade  wastes  interfere  with  the  process.  The  process  can  be 
operated  in  cold  weather.  Clarification  is  independent  of  nitrification. 

225  Aerating   apparatus.     C.   H.   NORDELL,  Milwaukee,  Wis.     U.   S.   Patent 
1,208,821,  Dec.  19,  1916.     (Application  filed  March  23,  1916.     1  claim.) 

Off.  Gaz.  233,  800.  Jour.  Soc.  Chem.  Ind.  36,  201.  A  container  for  sludge 
having  a  bottom  composed  of  wooden  slabs  cut  transversely  of  the  grain  to 
form  minute  elastic  air  passages  for  air,  a  casing  below  the  wood  slab  bottom 
forming  an  air  chamber,  and  a  means  for  introducing  air  under  pressure  into 
the  chamber  whereby  it  is  forced  through  the  fibrous  passages  of  the  wood 

43 


The  Activated  Sludge  Process 

slabs  to  form  minute  bubbles  for  uniformly  aerating  the  body  of  sludge  that 
is  supported  by  the  fibrous  bottom.  (Cf.  U.  S.  Patent  1,281,816.  Ref  No 
427). 

226  Community  activated  sludge  plant  for  Chicago  stockyards.    NEWS  ITEM. 
Eng.  Record  74,  784.     Engineers  of  the  stockyards    interests  and  the 

Sanitary  District  of  Chicago,  after  making  a  joint  study  of  the  proper  dis- 
posal system,  agree  that  the  activated  sludge  method  will  handle  the  sewage 
and  conclude  that  a  community  plant  to  take  care  of  all  the  wastes  from  all 
the  packing  industries  is  better  than  the  disposal  by  each  company  of  its 
own  wastes. 

227  Third  Annual  Report  of  the  Milwaukee   Sewerage   Commission.     T.   C. 

HATTON  and  W.  R.  COPELAND.  Pamphlet  pp.  127.  (Dec.  31,  1916)  An 
elaborate  report  on  the  activated  sludge  work  for  the  year  ending  Dec.  31, 
1916,  at  the  sewage  testing  station.  Of  all  the  processes  experimented  with, 
the  activated  sludge  process  appears  to  be  the  only  one  which  fits  the  exist- 
ing conditions  in  Milwaukee.  The  maximum  volume  of  air  required  to  pro- 
duce a  stable  effluent  from  which  95%  bacteria  and  98%  suspended  solids 
have  been  removed,  is  2  cu.  ft.  per  gallon  of  sewage,  based  on  10  ft.  depth 
of  sewage  in  the  aerating  tank.  Maximum  aeration  period,  4  hours,  and  the 
percentage  of  sludge  carried  may  vary  from  15  to  25  without  materially 
effecting  the  results.  Sedimentation  period  required  is  from  40  to  50  min- 
utes, with  a  maximum  horizontal  velocity  of  3  ft.,  and  a  vertical  velocity 
of  about  8  inches  per  minute.  Slopes  for  successfully  removing  settled  sludge 
should  be  from  1  to  2,  to  1  to  3.  Breaking  up  the  air  into  small  bubbles 
increases  the  O  absorbed,  but  sufficient  air  must  be  used  to  manitain  the 
solids  in  suspension.  Filtros  plates  are  satisfactory  air  diffusers,  but  all 
oil  and  dust  should  be  excluded  from  the  air  lines.  Wood  plates  give  smaller 
bubbles  than  filtros  at  less  loss  of  pressure,  but  insufficient  experience  does 
not  warrant  their  adoption.  Sewage  can  be  clarified  in  from  1  to  1.5  hours 
aeration  in  the  presence  of  well  activated  sludge,  by  using  0.5  to  1  cu.  ft. 
of  air  per  gallon  of  sewage  in  a  10  ft.  deep  tank,  but  the  activity  of  the 
sludge  cannot  be  maintained  without  additional  aeration.  Storm  flow  can 
be  taken  care  of  by  increasing  the  volume  of  air  and  sludge,  but  extra 
settlement  capacity  must  be  provided  if  a  standard  effluent  is  to  be  main- 
tained. Conduits  should  not  be  used  as  the  sludge  settles  too  quickly.  Re- 
covered sludge  contains  99%  of  water,  which  may  be  reduced  to  96%  by 
additional  settlement  of  1  to  3  hours.  Over-aeration  reduces  its  volume  and 
also  its  coagulating  properties.  Sludge  can  be  dewatered  from  96  to  75% 
by  presses  without  the  use  of  lime,  and  from  75  to  10%  by  either  indirect 
steam,  or  direct  heat  dryers,  without  appreciable  loss  of  ammonia.  Milwau- 
kee sludge,  on  a  dry  basis,  contains  4.5  to  5%  ammonia.  With  4  hours  aera- 
tion and  2  hours  settlement,  8  million  gallons  of  sewage  can  be  treated  upon 
1  acre.  About  80  pages  of  analytical  and  other  data,  and  several  illustra- 
tions accompany  the  report. 

228  A  few  figures  on  the  building  and  operation  of  the  Baltimore  disposal 
plant  and  notes  on  the  activated  sludge  experiments.     G.  J.  REQUARDT. 

Proc.  Am.  Soc.  Munic.  Impvts.  23,  416-28.  Refers  to  the  activated  sludge 
experiments  made  in  the  converted  Imhoff  tank  with  the  umbrella-like  dif- 
fuser  grids. 

229  A  year's  progress  in  activated  sludge  sewage  treatment.    T.  C.  HATTON. 
Proc.  Am.  Soc.  Munic.  Impvts.  23,  404-15.     Covers  operation,  the  secur- 
ing of  the  activated  sludge,  aeration,  the  effects  of  low  temperatures,  sedi- 
mentation, sludge  disposal,  and  general  notes  on  the  Milwaukee  experimental 
work.     More  fully  abstracted  from  the  annual  reports,  Ref.  Nos.  100  and  227. 

230  Discussion  of  papers  on  activated  sludge.    Proc.  Am.  Soc.  Munic.  Impvts. 
23,  439-43.     Covers  oral  and  written  discussion  of  the  papers  mentioned 

in  references  195,  203,  228  and  229.     Participated   in  by  Messrs.   HATTON, 

44 


Abstract  Bibliography — 1917 

COPELAND  and  NORDELL  of  Milwaukee;  Messrs.  FOLWELL,  FULLER  and  POTTER 
of  N.  Y.  City;  MR.  E.  B.  PHELPS  of  the  U.  S.  Public  Health  Service;  MR.  J. 
R.  ELLIS  of  Regina,  Canada;  (whose  letter  describes  quite  fully  the  activated 
sludge  experiments  in  that  city) ;  MR.  G.  L.  NOBLE  of  Chicago;  MR.  W.  T. 
CARPENTER  of  Brooklyn;  and  MR.  W.  L.  STEVENSON  of  Philadelphia,  Pa. 

231  Report  of  the  Committee  on  Sewage  and  Sanitation.    G.  A.  CARPENTER. 
Proc.  Am.  Soc.  Munic.  Impvts.  23,  324-6.     "It  is  very  generally  recog- 
nized that  the  activated  sludge  method  is  yet  in  the  process  of  development, 
and  should  not  be  adopted  except  under  expert  advise.     Thus  far  the  con- 
ditions necessary  for  success  have  not  been  sufficiently  standardized  to  jus- 
tify the  adoption  of  this  method  by  small  communities  and  the  great  prob- 
lem with  reference  to  it  today  is  the  question  of  cost." 

232  Water  purification  and  sanitation.    F.  R.  O'SHAUGNESSY.   Ann.  Report  of 
the  Soc.  Chem.  Ind.  of  the  Progress  of  Appl.  Chem.  1,  265-7.     (1916). 

A  brief  general  review  of  the  activated  sludge  process  for  the  year  1916. 
English  plants  mentioned  are  those  at  Manchester,  Worcester,  Salford,  Stam- 
ford and  Sheffield.  Milwaukee  experiments  and  the  work  at  the  Univ.  of  111., 
Urbana,  are  the  only  American  plants  considered. 

233  Experiments  upon  the  purification  of  sewage  and  water  at  the  Lawrence 
experiment   station   during  the   year   1916.     H.   W.    CLARK.    2nd.   Ann. 

Report  Mass.  State  Dept.  Health.  123-57.  Continuation  of  some  of  the 
earlier  experiments  are  recorded,  with  generally  favorable  results  as  shown 
by  the  removal  of  suspended  matter,  stability,  and  the  tabulated  data.  A 
new  and  larger  activated  sludge  tank  was  put  into  operation  on  the  fill  and 
draw  plan,  allowing  2.5  and  3.5  hours  for  aeration,  1.5  hours  for  settlement, 
and  with  air  supplied  at  the  rate  of  0.4  cu.  ft.  per  gallon  of  sewage,  through 
filtros  diffusers,  Investigations  have  shown  that  the  N  of  the  colloids  is 
from  2  to  3  times  as  great  as  the  N  of  the  coarser  solids  of  the  sludge,  which 
fact  increases  the  N  content  of  the  sludge  about  33%,  except  in  the  case  of 
tannery  sewage.  Investigations  of  paper  mill  and  tannery  trade  wastes  by 
the  activated  sludge  process,  and  several  tables  of  chemical  and  bacteriological 
data  are  included. 

234  Sewerage.    A.  P.  FOLWELL.     (Book)     Seventh  Edition,  468-70.     (1916). 
A  brief  history  and  present  status  of  sewage  treatment  by  aeration  and 

the  activated  sludge  process.  Refers  to  experiments  at  Manchester,  Eng.,  and 
Milwaukee,  Wis. 

1917 

235  A  new  method  of  purifying  tannery  and  other  effluents.    Y.  H.  GONONIAN. 
Leather  Manuf.  28,  45-9.     Chem.  Abst.  11,  1506.     A  preliminary  report 

in  which  the  author  discusses  briefly  the  subject  of  purification,  and  then 
gives  a  general  description  of  his  treatment  which  involves  oxidation,  chem- 
ical precipitation,  and  filtration.  The  crude  sewage,  screened  from  coarse  ma- 
terals,  is  mixed  with  activated  sludge,  slowly  passed  through  a  septic  tank 
and  gravity  tank,  and  fed  through  a  perforated  pipe  into  the  top  of  the 
filtration  and  oxidation  device.  The  latter  is  composed  of  a  series  of  5  large 
superimposed  tanks  fitted  with  false  bottoms.  Under  each  tank  except  the 
last,  there  passes  an  endless  belt  of  filter  cloth,  furnished  with  scrubbing 
brushes  and  washing  boxes,  which  are  in  turn  connected  to  the  settling  tanks. 
Tanks  for  chemicals  are  arranged  to  feed  automatically  on  to  the  first  three 
filter  cloths.  The  large  tanks  are  partly  filled  with  stones  and  gravel,  the 
fourth  one  in  the  series  having  a  perforated  pipe  connected  to  a  compressed 
air  or  ozone  generator  for  extra  aeration  when  necessary.  The  first  filter 
cloth  is  supplied  from  one  of  the  chemical  tanks  with  a  layer  of  coal  ashes, 
coal,  or  charcoal;  the  second  with  hydrated  lime;  the  third  with  aluminum 
sulphate.  The  effluent  in  passing  through  the  lime  is  made  alkaline,  which 

45 


The  Activated  Sludge  Process 

favors  the  coagulation  by  the  aluminum  sulphate  on  the  following  cloth. 
Further  aeration  in  the  fourth  tank  tends  to  complete  the  oxidation  and  pre- 
cipitation. Diagrams  are  given. 

236  The  activated  sludge  method  of  sewage  disposal.     E.  E.  SANDS.     Texas 
Municipalities    (Jan.   1917)    pp.   16-21.     A   paper  presented   at  the  4th 

Ann.  Conv.,  League  of  Texas  Munic.  held  on  Oct.  26,  1916,  giving  a  general 
description  of  the  activated  sludge  process,  and  account  of  the  experiments 
at  Houston,  Texas,  with  outline  of  the  proposed  plant  for  that  city. 

237  Activated   sludge  power   costs.     G.  J.   REQUARDT.     Eng.   News   77,   18. 
Ghent.  Abst.  11,  2517.     Curves  are  given  with  an  explanation  of  their 

use  for  computing  the  cost  of  the  compressed  air  which  may  be  required 
under  varying  conditions. 

238  Air  diffusers  for  activated  sludge.     EDITORIAL.     Munic.  Jour.  42,  11-2. 
Comments  on  the  merits   of  filtros  plates  for  that  purpose,  and   con- 
siders their  proper  handling  and  installation. 

239  Activated  sludge  process  of  sewage  disposal  firmly  established.     T.  C\ 
HATTON.    Eng.  Record  75,  16-9.     Chem.  Abst.  11,  679.     Refers  to  the 

several  plants  in  various  parts  of  the  country,  considers  types  of  sedimenta- 
tion tanks,  air  requirements  per  gallon  of  sewage  treated  and  its  cost,  de- 
watering  and  drying  of  the  sludge,  its  costs  and  value,  and  emphasizes  the 
importance  of  complete  supervision  over  the  process. 

240  Water  supply  and  sanitary  engineering  in  1916.     ANON.    Engineer  123, 
32-3.     A  general  review  of  the  progress  of  activated  sludge  work  during 

the  year.  Refers  to  the  Milwaukee  plant  and  the  extensive  experiments  there 
carried  on;  to  the  Salford,  Stamford,  and  Worcester  plants  in  England,  and 
to  DR.  RIDEAI/S  paper  on  the  recovery  of  N  from  sewage. 

241  Engineers  guide  sewage  disposal  inspection  trip.    P.  T.  HICKS  and  ED- 
WARD BARTOW.    Eng.  Record  75,  95-7.    Chem.  Abst.  11,  679.    Covers  the 

results  of  an  inspection  trip  by  a  party  from  Decatur,  111.,  refers  to  the  acti- 
vated sludge  plants  at  Brooklyn  and  Cleveland,  and  comments  on  the  dis- 
posal of  surplus  sludge. 

242  Sewerage  and  sewage  disposal.     The  activated  sludge  process.  EDITORIAL. 
Surveyor  51,  80-2.     Although  few  reports  on  activated  sludge  work  have 

been  published,  it  is  known  that  the  process  is  operating  in  about  6  places 
in  England.  Reference  is  made  to  the  plant  at  Worcester  treating  800,000 
gallons  per  day,  and  belief  is  expressed  that  after  the  war  the  activated 
sludge  process  will  be  adopted  in  many  places.  Utilization  of  the  sludge  is 
also  discussed. 

243  Activated  sludge   progress.     TRADE   NOTE.     Surveyor  51,   108.     In  col- 
laboration with  DR.  FOWLER'S  staff  at  Manchester  Univ.,  the  engineering 

staff  of  JONES  &  ATTWOOD  have  been  able  to  make  great  progress  along  scien- 
tific lines  in  the  activated  sludge  process.  Five  large  plants  have  been  in- 
stalled and  two  are  under  construction.  Diffusers,  aeration,  sludge  settle- 
ment and  treatment,  are  being  satisfactorily  solved. 

244  The  activated  sludge  process  of  sewage  purification.     E.  ARDERN.    Jour. 
Soc.  Chem.  Ind.  36,  65-8.    Surveyor  51,  298-9.    Jour.  Am.  Leather.  Chem. 

Assoc.  12,  128-35.  Chem.  Abst.  11,  2517.  Expt.  Sta.  Record  37,  286.  For  the 
purpose  of  comparing  the  effect  of  trade  wastes,  the  experimental  activated 
sludge  plant  previously  employed  on  the  Manchester  sewage — a  strong  trade 
sewage— was  transferred  to  the  Withington  sewage  works  where  a  purely 
domestic  sewage  is  dealt  with.  The  plant  consisted  of  wooden  casks  of  200 
liters  capacity.  Floating  matter  and  grit  was  removed  from  the  sewage  by 
adequate  detritus  tank  treatment.  Porous  tile  was  used  for  the  air  diffusers. 

46 


Abstract  Bibliography — 1917 

The  investigation  extended  over  a  period  of  15  months  with  the  following 
summary  of  results.  (1)  The  activated  sludge  produced  from  the  Withington 
sewage  has  an  appreciably  higher  nitrogen  content  than  either  the  Manchester 
or  Salford  sludge,  due  to  some  extent  to  the  fact  that  the  percenage  of 
mineral  matter  is  considerably  less.  (2)  That,  contrary  to  the  opinion  formed 
as  the  result  of  earlier  experiments  when  working  with  a  strong  trade  waste, 
the  maintenance  of  the  activity  of  the  sludge  is  not  dependent  on  the  stage 
to  which  nitrification  is  carried.  (3)  That  when  dealing  with  a  sewage  free 
from  inhibitory  trade  effluents,  no  appreciable  loss  of  efficiency  need  be  an- 
ticipated in  this  country  (England)  during  the  winter  months.  (4)  That 
while  the  problem  of  sludge  disposal  remains  to  be  fully  developed,  it  ap- 
pears from  known  data  that  the  cost  of  dewatering  and  drying  will  be  more 
than  repaid  by  the  value  of  the  resultant  dried  sludge.  Tabulated  data  and 
analyses  of  the  dried  sludge  are  given. 

245  Modern  sewage  treatment.     T.  C.  HATTON.     Jour.  West.  Soc.  Engrs.  22, 
87-100.     A  general  review  of  sewage  treatment  work  with  special  ref- 
erence to  the  activated  sludge  process.     Many  of  the  Milwaukee  experiments 
are   described,  particularly  those   relating  to  different  methods  of   aeration, 
sedimentation  and  sludge  treatment,  and  a  general  summary  of  the  results 
obtained  are  given.     The  practical  or  experimental  activated  sludge  plants  in 
several  cities  are  referred  to  and  their  plans  or  results  discussed.     The  author 
concludes  by  expressing  his  entire  confidence  in  the  process  because  it  gives 
greater  promise  of  satisfactorily  solving  a  complex  problem  than  any  other 
so  far  introduced. 

246  The  purification  of  sewage  in  the  presence  of  activated  sludge,  Illinois. 

E.  BARTOW,  F.  W.  MOHLMAN  and  J.  F.  SCHNELLBACH.  Jour.  West  Soc. 
Engrs.  22,  101-9.  (Discussion  109-15).  The  activated  sludge  plant  at  Cham- 
paign, 111.,  is  described.  Details  are  given  with  special  reference  to  the 
settling  chamber  and  retention  period  test,  the  amount  of  sewage  treated  daily 
during  the  different  periods  ranging  from  61,100  g.  p.  d.  to  177,600  g.  p.  d. 
The  authors  conclude  that  75,000  g.  p.  d.  could  be  satisfactorily  treated  with 
the  present  aerating  and  settling  capacity,  though  double  this  amount  could 
be  handled  in  the  aerating  tank  if  additional  sedimentation  were  provided. 
Sludge  dewatering  devices  are  considered.  In  the  discussion  following,  which 
included  also  the  paper  of  MR.  HATTON,  (Ref.  245)  PROF.  BARTOW,  LANGDON 
PEARSE,  PAUL  RUDNICK,  and  others  participated. 

247  The  Worcester  (Eng.)  activated  sludge  experiments.    T.  CAINK.  Surveyor 
51,  144.     A  letter  to  the  editor  to  correct  a  misstatement  in  a  previous 

article  that  air  was  delivered  intermittently  to  the  sewage  through  pulsating 
valves.  This  was  not  the  case,  the  air  being  delivered  continuously  through- 
out the  whole  period  of  the  experiments. 

248  Brushwood  as  a  medium  for  sewage  filters.    GEO.  PHELPS.   Can.  Engr.  32, 
117-21.     Eng.  Record  75,  376.     Surveyor  51,  254-5.     Engineer  123  337-8. 

Am.  City  16,  604-7.  Chem.  Abst.  11,  2517.  Expt.  Sta.  Record,  37,  489.  A 
description  of  the  North  Toronto,  Can.,  brushwood  filter  experiments,  citing 
the  similarity  between  the  conditions  here  and  those  of  the  activated  sludge 
process.  (Cf.  Ref.  No.  272). 

249  Notes  on  experiments  with  activated  sludge  at  Regina,  Can.    J.  RUSSEL 
ELLIS.     Can.  Engr.  32,  124-6.    Two  galvanized-iron  tanks  4.5  ft.  in  diam. 

by  5  ft.  10  in.  deep  were  used  with  perforated  pipe  covered  with  a  loose  fitting 
sleeve  of  canvas  for  air  diffusion.  The  plant  was  operated  on  the  fill  and 
draw  plan  with  cycles  of  6  to  12  hours  and  the  results  indicate  that  the 
process  is  adapted  to  local  conditions.  The  size  of  the  plant  did  not  warrant 
an  attempt  to  determine  the  cost  of  operation. 

47 


The  Activated  Sludge  Process 

250  How  sewage  plants  are  operating.     ANON.     Munic.  Jour.  42,  196-7.     Re- 
sume of  an  inspection  trip  by  officials  of  Pasadena,  Calif.,  on  which  sev- 
eral cities  were  visited  where  the  activated  sludge  process  is  in  use.     The  ex- 
cellent results  obtained  by  this  process  led  them  to  believe  that  it  will  even- 
tually supersede  all  others  where  a  high  degree  of  purification  is  necessary. 
They  also  find  that  it  occupies  less  space,  costs  less  for  construction,  is  abso- 
lutely odorless,  and  gives  a  better  effluent  than  the  Imhoff  tank  and  sprinkling 
filter  process.     The  cost  of  operation  is  greater,  however,  but  revenue  from 
the  sale  of  sludge  should  reduce  this  difference  in  costs.     They  express  hope 
that  the  sludge  may  be  dried  on  open  beds  in  a  warm  climate  like  southern 
California.     (Cf.  Ref.  Nos.  210  and  223). 

251  Activated  Sludge  plants  at  Houston,  Texas.     C.  L.  WILLIFORD.  Eng.  News. 
77,  236-8.     Two  activated   sludge  plants  with   a   combined  capacity  of 

19,000,000  gallons  a  day,  with  continuous  flow  aeration  tanks,  vertical  flow 
settling  tanks,  and  sludge  re-aeration  tanks  are  described  in  considerable 
detail.  One  plant  consists  of  four  units,  the  other  of  two  units,  each  unit 
having  a  rectangular  aerating  tank  280  by  18  feet  with  a  net  depth  of  9  ft. 
9  in.,  a  battery  of  10  vertical  flow  settling  tanks  and  one  sludge  re-aerating 
tank.  627  filtros  plates  are  contained  in  each  aerating  tank  in  112  frames  of 
6  plates  each.  The  ratio  of  aeration  surface  to  tank  surface  is  1  to  7.5.  Costs 
of  construction  and  operation  are  given. 

252  Activated  sludge  at  San  Marcos,  Texas.     H.  E.  ELROD.    Eng.  News  77, 
249.     Description  of  a  plant  having  a  capacity  for  treating  150,000  gal- 
lons of  sewage  daily.     It  consists  of  an  aerating  tank  40  by  16  by  8^   ft. 
deep  with  four  rows  of  filtros  plates  in  the  bottom,  and  a  settling  tank  25 
ft.  long,  10  ft.  wide,  25  ft.  deep  with  walls  having  a  vertical  batter  of  1  to  2. 
Effluents  have  a  relative  stability  of  99%   and  bacterial  reduction  amounts 
to  98%.    Total  cost  in  round  figures  was  $3,500. 

253  Sink  concrete  cofferdam  in  sand  for  activated  sludge  plant.    ANON.  Eng. 
Record  75,  228-9.     Description  of  work  on  the  activated  sludge  plant  at 

Escanaba,  Mich.,  which  will  treat  approximately  one  million  gallons  of  sew- 
age daily  on  the  continuous  flow  plan.  Filtros  plates  in  the  ratio  of  1  sq.  ft. 
aerating  surface  to  8.3  sq.  ft.  tank  surface  are  to  be  used  for  air  diffusers. 

254  Definitions  of  terms   used   in  sewerage   and   sewage   disposal   practice. 

ANON.  Eng.  &  Contg.  47,  168-9.  Can.  Engr.  32,  214-6.  A  report  of  a 
committee  of  the  Am.  Public  Health  Assoc.,  referring  to  the  activated 
sludge  process  as  in  reference  No.  202. 

255  Apparatus  for  aerating  sewage  and  other  foul  liquids.    R.  AMES,  Bright- 
on, Eng.     British  Patent  107,937,  Feb.  24,  1917.     Jour.  Soc.  Chem.  Ind. 

36,  977.  The  sewage  is  treated  in  a  rectangular  tank  over  which  is  a  traveling 
carriage  running  on  side  rails  and  bearing  a  drum  with  a  coil  of  flexible 
piping.  One  end  of  the  piping  is  connected  to  an  air  compressor  at  the  end 
of  the  tank,  and  the  end  of  the  drum  is  connected  to  a  horizontal  pipe  from 
which  vertical  pipes  depend  nearly  to  the  bottom  of  the  tank.  Air  diffusers, 
consisting  of  porous  clay  blocks  in  metal  casings,  are  affixed  to  the  ends  of 
the  vertical  pipes.  The  sewage  enters  at  the  bottom  of  the  tank  through 
an  inverted  U-shaped  pipe.  An  air  pipe  connected  to  the  compressor  enters 
the  upward  limb  of  the  U-shaped  pipe;  thus  air  can  be  passed  into  the 
sewage  entering  the  tank,  as  well  as  into  the  sewage  in  the  tank  from  the 
diffusers. 

256  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  and 
JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Eng.    British  Patent  113,333,  Feb. 

26,  1917.  Jour.  Soc.  Chem.  Ind.  37,  193A.  An  improved  form  of  tank  for  use 
in  the  activated  sludge  process  consists  of  a  long  channel  arranged  as  the 
outer  coil  of  a  spiral,  with  air  diffusers  placed  along  its  length,  either  in  the 

48 


Abstract  Bibliography — 1917 

middle  of  the  channel  or  at  one  or  both  sides.  The  floor  is  made  to  slope 
towards  the  air  diffusers.  The  channel  may  be  restricted  in  width  at  each 
end  or  at  the  position  of  the  air  diffusers  by  baffles  projecting  from  the 
side  walls.  The  channel  terminates  at  the  center  in  a  round  tank  with  a 
conical  bottom,  not  furnished  with  air  diffusers,  in  which  the  sludge  settles 
at  the  bottom  and  is  returned  by  an  air  lift  or  other  means  to  the  crude 
sewage  inlet  of  the  channel.  Another  form  of  the  channel  consists  of  a 
to  and  fro  rectangular  arrangement,  with  the  sludge  deposit  tank  at  one  end. 

257  Activated  sludge  tests  at  Pasadena,  Calif.     NEWS  ITEM.    Eng.  News  77, 
373.     The  aerating  chamber  has  a  capacity  of  50,000  gallons  per  day 

with  a  4  hour  aerating  period.  There  are  two  settling  tanks,  a  sludge  pump 
and  a  sludge  aerating  tank.  The  tests  are  in  charge  of  MR.  R.  V.  ORBISON 
who  reports  gratifying  results  and  that  a  plant  to  handle  3  to  6  million 
gallons  is  under  consideration. 

258  Worcester's    35-year    grapple   with    sewage    disposal    problems.     W.   L. 

BUTCHER.  Eng.  News  77,  384-5.  Chem.  Abst.  11,  2517.  Reviews  the 
history  of  sewage  disposal  at  Worcester  (Mass.)  and  refers  to  the  contem- 
plated activated  sludge  experiments. 

259  San  Marcos,  Texas,  activated  sludge  plant.    G.  B.  ZIMMELE,  Munic.  Jour. 
42,  333-5.     Chem.  Abst.  11,  1225.     This  is  believed  to  be  the  first  acti- 
vated sludge  plant  to  go  into  regular  operation  treating  the  entire  volume 
of  sewage  of  a  city.     Operations  were  commenced  April  27,  1916.     The  raw 
sewage   is   settled   in   a   tank   40   ft.   diam.   by  9   ft.   deep,   with   inflow   and 
outflow  at  different  points,  which  serves  to  remove  the  gross  material.     From 
this  it  flows  to  the  aerating  tanks,  4  in  number,  39  ft.  by  4  ft.  by  8  ft.  extreme 
depth,   and   connected   in   series.      Air   is   diffused   through   filtros   plates   set 
in   concrete   with   special   provision   for   draining   the   air   chamber   beneath. 
Aerating  period  2.5  to  5  hours.     The  sedimentation  chamber  is  20  ft.  by  10 
ft.  and  has  a  depth  of  about  25  ft.  with  bottom  slopes  of  2  to  1,  a  period  of 
1  to  2  hours  being  allowed  for  settling.     Baffles  are   also  provided  in  this 
tank.     About  150,000  gallons  of  sewage  are  treated  daily,  from  a  population 
of  about  5,000.     The  blower  has  a  capacity  of  230  cu.  ft.  per  minute. 

260  Worcester  sewage  treatment  history.     EDITORIAL.    Eng.  News  77,  406. 
It  is  to  be  hoped  that  Worcester  (Mass.)  will  give  the  activated  sludge 

process  as  full  a  test  as  may  be  needed  to  determine  its  suitability  for  local 
conditions.  The  Brockton  (Mass.)  activated  sludge  experiments  are  also 
referred  to. 

261  Operate  continuous  flow  activated  sludge  plant.     ANON.   Eng.  Record  75, 
380-1.     Abstract  of  article  by  BARTOW,  MOHLMAN  and   SCHNELLBACH, 

covered  by  references  211,  246. 

262  Activated  sludge  plant  for  Chicago  packinghouse  district.     NEWS  ITEM. 
Eng.  News.  77,  454.     An  activated  sludge  plant  for  treating  the  sewage 

and  industrial  wastes  from  the  Chicago  packinghouse  district  has  been 
recommended  by  the  committee  appointed  to  consider  the  question.  The  cost 
is  estimated  at  $3,500,000  with  an  annual  operating  expense  of  $800,000. 
The  committee  was  composed  of  LANGDON  PEARSE,  Division  Eng.  of  the 
Sanitary  District  of  Chicago,  and  DR.  W.  D.  RICHARDSON,  chemist  for  the 
packinghouse  companies. 

263  Experiments  relating  to  the  activated  sludge  process  of  sewage  purifi- 
cation.    W.  T.   LOCKETT.     Jour.  Soc.  Chem.  Ind.  36,  264-9.     Jour.  Am. 

Leather  Chem.  Assoc.  12,  199.  Chem.  Abst.  11,  2128.  Some  small  scale  ex- 
periments were  made  with  sewage  of  "average"  strength,  which  contained 
a  variety  of  trade  wastes,  some  of  them  of  inimical  character.  Special  atten- 
tion was  given  to  (1)  the  volume  of  air  required  for  the  efficient  working  of 

49 


The  Activated  Sludge  Process 

the  process,  (2)  possible  means  of  effecting  economy  of  air,  (3)  experi- 
ments relating  to  the  maintenance  of  sludge  activity  and  (4)  the  bacterio- 
logical nature  of  the  effluent.  The  conclusions  reached  were  (1)  air  in  ex- 
cess of  that  required  for  adequate  mixture  and  circulation  of  the  sewage 
and  sludge  is  of  no  material  advantage.  (2)  Sludge  and  sewage  in  the  pro- 
portions of  1  :  4  required  more  air  for  equivalent  results  than  when  the 
proportion  was  2  :  3.  Intermittent  aeration  suggested  by  MR.  W.  MAKEPEACE 
was  tried  and  the  fact  definitely  established  that  sewage  can  be  purified  with 
reduced  expenditure  of  air  by  this  method,  but  the  time  necessary  is  materi- 
ally increased  and  larger  tank  capacity  would  be  required.  The  evidence 
thus  far  accumulated  does  not  warrant  a  general  recommendation  of  this 
method  but  further  experiments  are  in  progress  which  may  eventually  have 
practical  importance.  (3)  Activity  of  the  sludge  can  be  recovered  by  pro- 
longed aeration,  even  after  standing  for  several  days.  (4)  Although  bac- 
terial removals  of  99%  and  upwards  were  obtained,  and  effluents  of  excep- 
tional clarity  and  eminently  satisfactory  from  a  chemical  point  of  view  also 
obtained,  B.  coli  above  1,000  per  c.  c.  were  present  when  the  raw  sewage 
was  correspondingly  high  in  these  organisms. 

264  The  activated  sludge  process.    EDITORIAL.   Surveyor  51,  297.     Comment- 
ing upon  the  paper  of  DR.  E.  ARDERN  (Ref.  No.  244)  it  is  noted  that  the 

process  adapts  itself  to  the  needs  of  particular  cases.  Domestic  sewage,  trade 
wastes,  storm  flow,  etc.,  can  be  handled  and  the  extent  to  which  purification 
is  carried  can  be  adjusted  to  a  nicety.  Such  conditions  indicate  the  possibility 
of  bringing  down  operating  costs  and  increasing  the  application  of  the 
process. 

265  The  activated  sludge  process  of  sewage  purification.     E.  ARDERN.    Sur- 
veyor  51,  299-300.     In  the  discussion  of  this  paper  MR.  J.  H.  HOSEASON, 

MR.  S.  E.  MELLING,  MR.  W.  THOMPSON  and  MR.  P.  GAUNT  brought  up  ques- 
tions of  sludge  digestion,  possible  recovery  of  the  N  as  sulphate  of  ammonia, 
of  using  peat  as  a  dilutent  for  the  sludge,  and  the  question  of  more  or  less 
complete  nitrification  on  the  saving  of  time  in  the  process. 

266  Activated  sludge  plant  at  Edmonton,  Canada.     ANON.    Can.  Engr.  32, 
265.      An   account   of   the   plant   and   the   experimental   work   done    at 

Edmonton,  taken  from  a  pamphlet  on  activated  sludge  by  G.  T.  HAMMOND. 
Details  of  aerating  chambers,  motor  equipment,  and  air  plant  are  given. 

267  Is  the  recovery  of  nitrogen  in  sewage  sludge  practicable?     W.  R.  COPE- 
LAND.   Jour.  Ind.  Eng.  Chem.  9,  374-6.     Jour.  Soc.  Chem.  Ind.  36,  517-8. 

Chem.  Abst.  11,  2008.  Expt.  Sta.  Record  37,  425.  Summing  up  the  whole 
situation,  dried  sludge  has  a  market  value  of  $9  to  $15  per  ton  of  material 
(present  figures)  with  10%  moisture.  The  total  cost  of  production  and 
placing  it  on  the  market  will  be  $8  to  $12  per  ton,  depending  on  local  con- 
ditions. Large  plants  may  reduce  this  cost  as  a  result  of  further  experience. 

268  Biochemical  treatment   of   sewage   with   special   reference   to  the   acti- 
vated sludge  method.    G.  T.  HAMMOND.  Jour.  Ind.  Eng.  Chem.  9,  399-403. 

Chem.  Abst.  11,  2008.  A  very  concise  and  complete  historical  sketch  is  given 
on  the  biochemical  treatment  of  sewage  and  its  newest  application  in  the 
activated  sludge  process.  Though  it  is  yet  in  the  experimental  stage,  this 
method  seems  very  promising.  Many  problems  are  yet  to  be  solved,  par- 
ticularly methods  of  aeration,  sludge  disposal,  and  biological  control. 

269  Sewage  treatment  units.    J.  W.  ALVORD,  H.  P.  EDDY,  and  G.  W.  FULLER. 
Munic.  Jour.  42,  526.     In  a  report  to  the  North  Shore  Sanitary  District 

the  authors  give  the  following  basic  data  used  by  them  in  preparing  plans  for 
sewage  treatments  considered  in  the  report.  "Activated  sludge — Minimum 
period  of  aeration  (during  maximum  rate  of  flow),  3  hours,  1  2-3  cu.  ft.  of 
air  per  gallon  of  sewage  treated  in  aerating  tanks  15  ft.  deep.  Sedimentation 

j 

50 


Abstract  Bibliography — 1917 

tank  providing  one  hour's  sedimentation  at  maximum  rate.  Sludge  storage 
tank,  capacity  for  10  days  output.  Sludge  drying  bed  3  1-3  sq.  ft.  per  capita; 
or  sludge  presses  for  %  to  1  ton  of  dry  sludge  per  10,000  people." 

270  Activated  sludge  vs.  tanks  and  filters.     EDITORIAL.   'Surveyor  51,  359. 
Comment  on  paper  by  H.  P.  EDDY.    (Ref.  No.  217).     Relative  areas  of 

land  necessary  will  govern  choice  in  most  cases.  Small  loss  of  head  in  the 
activated  sludge  process  will  be  in  its  favor,  as  well  as  the  superior  quality 
of  the  effluent. 

271  The   activated   sludge   process   for   handling   packingtown   trade   wastes. 

LANGDON  PEARSE  and  W.  D.  RICHARDSON.  Report  to  the  Board  of 
Trustees  of  the  Sanitary  District  of  Chicago,  pp.  36.  (April  16,  1917). 
Suggestions  or  recommendations  include  grit  chamber,  with  additional  fa- 
cilities for  skimming  grease;  coarse  bar  followed  by  fine  screens;  aerating 
tanks  in  32  units,  each  160  ft.  by  38.333  ft.  by  16.5  ft.  deep,  divided  longitud- 
inally and  of  1.5  million  gallons  daily  capacity;  air  diffusion  through  filtros 
plates,  the  area  of  which  to  the  superficial  area  of  the  tank  is  about  1  to  6; 
air  washers  to  be  installed  ahead  of  compressors;  continuous  flow  system  with 
8  hour  contact  period  and  4  cu.  ft.  of  air  per  gallon  of  sewage;  settling  tanks 
of  the  circular  Dortmund  type,  30  ft.  inside  diam.  with  hopper  bottom  on  a 
slope  of  60  degrees,  and  with  a  water  depth  of  33.5  ft.;  settling  period, 
1  hour;  sludge  handling  open  to  various  expedients  but  from  the  standpoint 
of  the  recovery  of  values,  filter  pressing  and  heat  drying  only  have  been 
demonstrated.  Plant  cost  estimated  at  $3,751,535,  with  an  annual  operating 
cost  of  $821,947,  of  which  $270,000  is  for  power.  Revenues  expected  per  mil- 
lion gallons  of  sewage  are: — 600  to  1,000  Ibs.  dry  screenings;  47  Ibs.  grease, 
and  1,500  to  2,500  Ibs.  dry  sludge.  Tables,  maps,  analytical  and  other  data 
are  given. 

272  The  North  Toronto  brushwood  filters.     S.  H.  ADAMS.   Engineer  123,  375. 
Surveyor  51,  458.     Reference  is  made  to  the  experiments  with  brush- 
wood filters  and  some  fundamental  differences  between  this  method  of  sewage 
purification  and  the  activated  sludge  process  are  pointed  out.     The  principal 
reason  for  their  success  in  Canada  is  that  their  domestic  sewage  is  only  about 
half  the  strength  of  that  in  England.     (Cf.  Ref.  No.  248). 

273  Air  diffusion  in  activated  sludge.     W.  S.  COULTER.    Eng.  News-Record 
78,   255-6.     Surveyor  51,   506-7.     Chem.   Abst.   11,   2008.     Experiments 

indicate  the  possibility  of  prolonging  the  air  and  sewage  contact  period  by  a 
downward  jet  entraining  air. 

274  Separation  and  settlement  of  solids  and  semi-solids  from  sewage  and 
analogous  liquids.    W.  CLIFFORD,  Wolverhampton,  and  JONES  &  ATTWOOD, 

L'TD.,  Amblecote,  Eng.  Brtish  Patent  115,872,  May  17,  1917.  Jour.  Soc. 
Chem.  Ind  37,  440A.  A  tank  in  the  form  of  an  inverted  cone  is  used,  into 
which  the  sewage  is  brought  by  a  horizontal  pipe,  the  mouth  of  which  directs 
the  current  into  a  wide  bucket  suspended  in  the  upper  part  of  the  tank. 
This  has  the  effect  of  breaking  up  the  currents  and  causing  eddies  which  pass 
upwards  and  out  of  the  bucket.  These  eddies  are  prevented  from  spread- 
ing by  a  guard  wall  of  much  larger  diameter,  surrounding  the  bucket  and 
carried  upwards  above  the  level  of  the  liquid  in  the  tank.  The  guard  wall 
is  open  at  the  bottom,  and  the  liquid  passes  from  it  at  a  low  velocity  and 
without  any  disturbing  effect  on  the  deposited  sludge  in  the  bottom  of  the 
tank.  The  liquid  finally  passes  out  of  the  tank  over  a  weir  at  the  circum- 
ference. The  sludge  is  withdrawn  through  a  pipe  in  the  apex  of  the  cone. 

275  Decanting  and  settling  chemcal  and  other  liquids.    W.  CLIFFORD,  Wolver- 
hampton, and  JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Eng.    British  Patent 

117,472,  May  24,  1917.  Jour.  Soc.  Chem.  Ind.  38,  497A.  Chem.  Abst.  IS,  502. 
In  the  separation  and  settlment  of  suspended  matters  from  chemical  and 

51 


The  Activated  Sludge  Process 

like  manufacturing  liquids,  providing  at  or  near  the  top  of  the  settlement 
tank  a  bucket  or  like  vessel  by  which  the  liquid  from  the  inlet  is  directed 
upwardly  into  a  relatively  large  body  of  liquid  within  an  open-bottomed 
guard  chamber  or  well,  which  directs  the  slowly  moving  liquid  downward 
into  the  body  of  the  liquid  in  the  tank.  In  a  modification,  the  bucket  or  like 
vessel  is  replaced  by  a  funnel-shaped  vessel  carried  at  the  end  of  the  inlet 
pipe,  and  adapted  to  direct  the  flow  upwards.  (Cf.  U.  S.  Patent  1,343,764. 
Ref.  No.  565). 

276  Marked  advance  in  treating  sewage  from  packinghouses.    G.  B.  ZIMMELE. 
Eng.  News-Record  78,  436-7.     Surveyor  52,  252.     Chem.  Abst.  11,  2246. 

Expt.  Sta.  Record  37,  694.  An  experimental  activated  sludge  plant  at  Fort 
Worth,  Tex.,  is  equipped  with  revolving  screen  and  settling  tanks,  treating 
packinghouse  wastes  containing  3000  to  6000  p.  p.  m.  suspended  matter.  Even 
when  screened  and  settled,  this  sewage  is  too  strong  for  the  activated  sludge 
process,  and  must  be  diluted  with  either  4  parts  of  water  or  1  part  of  treated 
effluent.  35%  sludge  during  aeration  is  better  than  25%,  and  separate  aera- 
tion of  the  sludge  is  advisable.  The  effluent  is  stable  and  can  be  re-used  in 
the  packinghouse.  The  dewatering  of  the  sludge  by  acidulation  and  heat 
has  given  great  promise;  this  method  reducing  the  water  content  from  99 
to  85%,  and  increasing  the  ammonia  content  from  8  to  11%.  (Cf.  Ref. 
No.  291). 

277  The  operation  of  the  activated  sludge  type  of  sewage  plants.    G.  B.  GAS- 
COIGNE.     Ohio  Eng.  Soc.  Proc.  (1917)   pp.  79-86.     A  general  description 

of  the  process,  the  necessary  plant,  its  operation,  the  sludge  dewatering 
problem,  estimated  costs,  and  the  method  of  recording  results  are  given. 

278  Sewage  treatment:  activated  sludge  system.     JONES  &  ATTWOOD,  L'TD. 
Booklet  No.  52,  pp.  18.     (June,  1917.)     A  detailed  description  of  the  acti- 
vated sludge  plant  at  Worcester,    (Eng.)    covering  structural  features;    air 
compression,  distribution,  and  diff users ;  operating  data ;  degree  of  purification 
obtained  and  running  costs.     The  pulsating  gear  for  supplying  air  intermit- 
tently is  described,  and  some  data  on  the  fertilizing  properties  of  activated 
sludge  given. 

279  Report  of  the  city  engineer  upon  an  experiment  with  the  activated  sludge 
process  of  sewage  purification.    THOS.  CAINK.    Pamphlet  pp.  12.     (June 

13,  1917.)  Deals  particularly  with  the  terms  between  the  contractors  and  the 
city  of  Worcester  (Eng.),  and  compares  costs  of  the  activated  sludge  process 
with  that  of  the  old  system. 

280  Activated  sludge  experimental  work  at  Milwaukee.    T.  C.  HATTON.    Can. 
Engr.  32,  491-4.    Chem.  Abst.  11,  3074.    Data  from  the  3rd.  Ann.  Report 

of  the  Milwaukee  Sewerage  Com.  Results  of  the  work  are  given  with  details 
of  the  sludge  pressing  experiments.  It  is  concluded  that  for  Milwaukee  sewage, 
the  activated  sludge  process  will  work  with  2  cu.  ft.  of  air  per  gallon  of  sewage. 
With  a  4  hour  aeration  period  and  15  to  20%  sludge  present,  40  to  50  minutes 
sedimentation  is  required  and  a  maximum  horizontal  velocity  of  3  ft.  per  min- 
ute, and  vertical  velocity  under  8  inches  per  minute.  Dried  sludge  contains 
4.5  to  5%  ammonia. 

281  Activated  sludge  in  India.    NEWS  ITEM.    Eng.  News-Record  78,  535.    DR. 
G.  J.  FOWLER  has  reported  on  the  possibility  of  dealing  with  the  sewage 

of  Sakchi,  India,  a  settlement  of  the  Tanta  Steel  Works  with  a  future  popula- 
tion of  150,000,  by  the  activated  sludge  process. 

282  The  activated  sludge  process  at  Worcester,  (Eng.)     THOS.  CAINK.    Sur- 
veyor 51,  546-8.    The  tests  undertaken  by  JONES  &  ATTWOOD  (Ref.  Nos. 

172  and  284)  were  started  April  25,  1916.  The  sewage  is  screened  and  grit 
removed  before  entering  the  aerating  tanks,  which  are  18  ft.  deep,  baffled,  and 

52 


Abstract  Bibliography — 1917 

provided  with  porous  tile  diffusers.  Aeration  period  8  hours,  using  0.8  cu.  ft. 
of  air  per  gallon  of  sewage.  Two  settling  tanks  have  hopper  bottoms  with  60 
degree  slopes,  where  the  sludge  is  detained  for  2.25  hours,  being  then  returned 
by  air  lifts.  The  sludge  may  be  dried  on  land  if  applied  in  layers  of  one  inch, 
without  development  of  odors.  Conditions  of  tests  were  fully  met.  Plant  and 
results  are  more  completely  described  in  a  pamphlet  issued  by  JONES  &  ATT- 
WOOD.  (Ref.  No.  278.) 

283  The  activated  sludge  process  at  Worcester,  (Eng.)     EDITORIAL.    Surveyor 
51,  544-5.     Comment  on  the  paper  by  T.  CAINK  (Ref.  No.  282),  who  was 

responsible  for  the  activated  sludge  installation.  Cost  data  should  be  given 
in  detail.  Porous  plate  diffusers  are  most  successful  in  England. 

284  Activated  sludge  plant  at  Worcester,  (Eng.)     JONES  &  ATTWOOD.    Sur- 
veyor 51,  549.     Chem.  Abst.  11,  3074.     Complete  results  of  the  experi- 
mental work  at  Worcester  are  given.     The  tank  used  was  80  ft.  long  by  72  ft. 
wide,  divided  into  9  longitudinal  sections  of  which  5  were  used  for  aeration 
and   4  for  settling.     Air  was  diffused  through  porous  tiles   and  no  trouble 
through  clogging  has  been  encountered  with  clean  air.    The  amount  of  sewage 
treated  on  the  continuous  flow  plan  varied  from  600,000  to  1  million  gallons 
per  day.     An  interesting  temperature  chart  is  given,  showing  sewage,  effluent 
and  air  temperatures  during  the  winter  months. 

285  Apparatus  for  aerating  sewage  and  other  foul  liquids.    R.  AMES,  Brighton, 
Eng.  British  Patent  115,933,  June  19,  1917.     Jour.  Soc.  Chem.  Ind.  37, 

440A.  The  sewage  enters  a  channel  located  alongside  a  treatment  tank,  from 
which  it  is  siphoned  into  a  trough  which  travels  over  the  tank.  The  sewage 
flows  into  the  tank  through  vertical  pipes  with  bell-mouths,  which  depend  from 
the  trough  to  the  bottom  of  the  tank.  Other  pipes  pass  down  the  centers  of 
the  vertical  pipes  and  carry  horizontal  fans  at  their  lower  ends,  adapted  to 
revolve  inside  the  bell-mouths,  whereby  vortices  are  created  and  air  drawn 
down  the  pipes.  The  blades  of  the  fans  are  hinged  in  order  to  permit  of  the 
fans  being  drawn  up  the  pipes  when  they  require  cleaning.  A  further  supply 
of  air  is  obtained  through  a  pair  of  tubes  extending  from  the  surface  to  the 
inside  of  each  bell-mouth. 

286  Recommend  50,000,000  gallon  activated  sludge  plant.    ANON.    Eng.  News- 
Record  78,  594-6.    Eng.  &  Contg.  48,  28-30.    Chem.  Abst.  11,  3074.    Joint 

committee  representing  the  Chicago  Sanitary  District  and  the  packers  recom- 
mend a  50  million  gallon  per  day  activated  sludge  plant  for  treating  stockyards 
sewage,  but  advise  a  six  months  trial  of  a  1.5  million  gallon  unit.  Digest  of 
the  report  of  PEARSE  and  RICHARDSON,  Ref.  No.  271. 

287  Activated   sludge   bibliography.     NEW   LITERATURE   NOTE.     Eng.  News- 
Record  78,  604.     Eng.  &  Contg.  49,  354.     Chem.  Abst.  11,  3076.     Expt. 

Sta.  Record  38,  691.    Refers  to  the  first  edition  of  this  bibliography. 

288  Milwaukee  air-diffusion  studies  in  activated  sludge.    C.  H.  NORDELL.    Eng. 
News-Record  78,  628-9.     Chem.  Abst.  11,  2517.     The  problem  is  to  pro- 
long contact  with  sewage  by  subdividing  the  air  into  small  enough  bubbles  so 
that  their  speed  of  ascent  is  lessened.     From  25  to  50%  of  the  tank  area  must 
be  diffusing  area  or  the  bubbles  will  coalesce  rapidly.     This  fact  eliminates 
the  use  of  nozzles  and  mechanical  beaters.     Further  studies  are  being  made 
to  perfect  fine-bubble  diffuser  plates. 

289  Purification  of  tannery  wastes.     H.   B.   HOMMON.     Jour.  Am.  Leather 
Chem.  Assoc.  12,  320.    In  discussion  of  this  paper,  V.  KADISH  stated  that 

the  activated  sludge  process  had  been  tried  at  a  chrome  tannery  in  Milwaukee. 
It  worked  well  with  soak  liquors  and  also  sulphide  liquors  if  not  too  concen- 
trated. 

53 


The  Activated  Sludge  Process 

290  Buffalo  Meeting  of  the  Am.  Inst.  Chem.  Engrs.     ANON.     Met.  &  Chem. 
Eng'rg.  17,  6.     Abstract  of  a  paper  on  the  activated  sludge  process  by 

DB.  E.  BARTOW.     (Cf.  Ref.  No.  310.) 

291  Treating  packinghouse  sewage.     G.   L.  NOBLE.     Eng.  News-Record  79, 
33.    A  letter  to  the  editor  to  correct  an  article  by  G.  B.  ZIMMELE,  (Ref. 

No.  276)  refuting  the  statement  that  the  effluent  from  the  activated  sludge 
sewage  plant  is  re-used  in  the  packinghouse  like  ordinary  water.  It  is  also 
suggested  that  the  statement  respecting  acid  treatment  of  the  sludge,  be  con- 
fined to  Fort  Worth  conditions  only. 

292  Sewage  aeration  and  activated  sludge.    ANON.    Engineering  104,  16-17. 
A  general  review  of  the  origin  and  development  of  the  activated  sludge 

process.  Refers  to  the  work  of  BLACK  and  PHELPS  at  Brooklyn;  CLARK  at 
Lawrence;  FOWLER  and  ARDERN  &  LOCKETT  at  Manchester;  DUCKWORTH  and 
MELLING  at  Salford;  BARTOW  and  MOHLMAN  at  Urbana;  HATTON  at  Milwau- 
kee; NOBLE  and  RUDNICK  at  the  Chicago  stockyards;  the  plants  at  Baltimore, 
Houston,  Brockton;  and  the  trial  of  the  process  on  tannery  wastes  at  Norwood, 
Mass. 

293  Worcester   (Eng.)   activated  sludge   plant.     NEWS  ITEM.     Surveyor  52, 
10.     The  Worcester  City  Council  accepts  recommendations  made  by  the 

water  and  sewage  committee  to  purchase  the  activated  sludge  plant  installed 
by  JONES  &  ATTWOOD  for  experimental  purposes. 

294  Air  lifts  for  activated  sewage  sludge.    T.  CAINK,  Worcester,  Eng.    British 
Patent  116,580,  July  7,  1917.    Jour.  Soc.  Chem.  Ind.  37,  484A.    A  vertical 

pipe  is  arranged  with  its  lower  openings  near  the  floor  of  the  settling  chamber, 
and  its  upper  end  surrounded  by  an  annular  chamber  having  a  weir  at  one 
side  over  which  the  sewage  flows  to  another  chamber,  and  thence  to  the  aerating 
tank.  Air  is  supplied  through  a  small  concentric  vertical  pipe  having  its  lower 
end  terminating  in  a  porous  air  diffuser,  through  which  the  air  rises  into  the 
lift  pipe,  carrying  the  sludge  with  it.  A  gage-tube  is  provided  on  the  annular 
chamber,  so  that  the  height  of  the  liquid  over  the  weir,  and  consequently  the 
rate  of  flow,  is  indicated.  The  proportion  of  sludge  is  indicated  by  the  amount 
of  solid  matter  settling  in  the  gage-tube. 

295  Activated    sludge    process    of    sewage    purification    at    Worcester,    Eng. 
T.  CAINK.    Engineering  104,  49-51.    Surveyor  52,  51-5.    Jour.  Soc.  Chem. 

Ind.  36,  938.  Can.  Engr.  33,  30;  38-40.  Chem.  Abst.  11,  3358.  A  paper  pre- 
sented at  the  annual  meeting  of  the  Assoc.  of  Mgrs.  of  Sewage  Disposal  Wks., 
July  7,  1917,  in  which  a  detailed  account  of  the  plant  is  given,  accompanied  by 
designs  which  show  the  lay-out  and  construction.  The  tank  used  has  a  ca- 
pacity of  626,000  gallons  and  is  divided  into  28  rectangular  bays,  20  for  aera- 
tion and  8  for  settling.  The  floor  is  on  the  ridge-and-furrow  principle  with 
porous  tile  diffusers  in  the  furrows.  These  diffusers  are  placed  5  ft.  apart  in 
the  first  bays  of  the  tank  receiving  the  raw  sewage,  and  10  ft.  apart  in  the 
other  bays.  The  floors  of  the  settling  bays  are  in  the  form  of  inverted  pyra- 
mids, in  the  apices  of  which  are  air  lifts  whereby  the  sludge  is  raised  to  a 
main  which  conveys  it  back  to  the  sewage  inlet  channel.  Excess  sludge  is 
drawn  off  to  a  sand  filter  for  drying.  The  purified  effluent  is  decanted  from 
the  settling  tank.  The  volume  of  sewage  treated  on  the  continuous  flow  plan 
is  750,000  gallons  per  day,  with  8  hours  aeration  and  2.5  hours  settling.  The 
area  of  the  diffusers  is  about  1-10  the  area  of  the  aeration  bays,  and  the  vol- 
ume of  air  used  is  0.8  cu.  ft.  per  gallon  of  sewage.  The  sludge  when  drained, 
contains  95%  water.  The  analyses  of  the  sewage  and  effluent  are  respectively 
as  follows  in  p.  p.  m.: — Solids  in  suspension,  104,  trace;  solids  in  solution,  1510, 
1430;  NaCl,  689,  677;  free  ammonia,  20,  26;  albuminoid  ammonia,  5.7,  1.7; 
O  absorbed  in  4  hours,  21,  5.6;  nitrates  and  nitrites,  none,  none.  Dissolved  O 
absorbed  by  the  effluent  in  5  days,  6.3 ;  stable  for  5  days  by  the  incubation  test. 
The  standard  to  which  it  must  conform  is  that  it  must  be  incapable  of  putrifica- 

54 


Abstract  Bibliography — 1917 

tion  and  shall  not  contain  more  than  40  p.  p.  m.  suspended  solids.     This  has 
been  met  in  dry  weather,  but  not  with  a  wet  weather  flow. 

296  A  resume  of  the  present  position  of  the  activated  sludge  process  of  sew- 
age purification.     E.  ARDERN.     Jour.  Soc.  Chem.  Ind.  36,  822-30.     Engi- 
neering 104,  134.     Engineer  124,  94.     Surveyor  52,  140-2.     Chem.  Abst.  11, 
3357.    The  paper  deals  more  particularly  with  typical  installations  with  which 
the  author  is  familiar,  or  respecting  which  authentic  information  is  available. 
The  English  plants  considered  are  those  at  Manchester,  Salford,  Worcester, 
and   Stamford,  while  the  following   American   plants   are  mentioned:      Mil- 
waukee, Houston,  and  the  111.  State  Water  Survey.    A  summary  of  the  progress 
of  the  method  is  given,  together  with  intimations  of  what  may  be  expected  in 
the  future. 

297  The  activated  sludge  process.     S.  BARWISE.    Surveyor  52,  40.     Describes 
the  principles  involved  in  this  method  of  sewage  treatment,  and  specu- 
lates as  to  the  various  methods  of  applying  these  in  the  future;  for  example, 
in  the  form  of  a  new  percolating  filter. 

298  Activated  sludge  treatment  at  Worcester.     (Eng.)     EDITORIAL.    Surveyor 
52,  45-6.    Remarks  on  the  paper  of  MR.  T.  CAINK  (Ref.  No.  295)  with  the 

intimation  that  further  investigation  of  the  effect  of  tarry  liquids — which  upset 
the  plant  at  Worceser  and  elsewhere — would  be  interesting. 

299  Assoc.  of  Mgrs.  of  Sewage  Disposal  Works  Meeting.    Discussion  of  papers. 
Surveyor  52,  67.     Referring  to  the  Worcester  activated  sludge  experi- 
ments, MR.  T.  CAINK  describes  the  incident  of  large  quantities  of  tarry  matter 
entering  the  tanks,  and  interfering  seriously  with  the  purification.     The  O 
absorption  in  the  sewage  rose  from  30  or  40  p.  p.  m.  to  140,  and  in  the  effluent 
from  8  p.  p.  m.  to  84.     The  latter  contained  only  28  p.  p.  m.  of  suspended 
matter,  however,  and  was  stable  for  5  days.     Antiseptics  of  this  or  any  other 
kind  should  be  kept  from  the  sewers,  as  they  operate  injuriously  against  any 
system  of  bacterial  purification.    MR.  W.  H.  DUCKWORTH  said  that  personally 
he  believed  there  was  a  great  future  for  the  activated  sludge  process  from 
several  points  of  view,  and  agreed  with  Mr.  Caink  that  it  was  probably  not 
equalled,  certainly  not  surpassed. 

300  Activated  sludge  process  of  sewage  disposal.     T.  CAINK.     Surveyor  52, 
87-8.     Replies  to  questions  raised  in  connection  with  the  author's  paper 

on  the  Worcester  activated  sludge  experiments.  (Ref.  No.  295.)  Refers  to 
air  requirements,  quantity  of  trade  waste  in  the  sewage,  contains  an  estimate 
of  construction  and  operating  charges  for  a  new  plant,  suggestions  for  the 
design  of  aerating  tanks  so  as  to  get  an  efficient  flow,  and  means  for  removing 
the  sludge. 

301  Activated    sludge    sewage    purification    plant   near    Worcester.      (Eng.) 
Engineering  104,  118-9.    Chem.  Abst.  12,  1224.    A  plant  for  an  Admiralty 

Airship  Station  with  a  population  of  400  is  described  and  illustrated.  Plans 
and  some  tabulated  data  are  given. 

302  Dewatering   sludge   at   Urbana    Sewage    Station.     ANON.     Eng.   News- 
Record  79,  269.     Abstract  from  a  portion  of  a  paper  on  the  activated 

sludge  process  by  DR.  E.  BARTOW.     (Cf.  Ref.  No.  310.) 

303  Filtros   plates  made  best  showing  in  air  diffuser  tests.     ANON.     Eng. 
News-Record  79,  269-70.     Abstract  from  a  portion  of  a  paper  on  the 

activated  sludge  process  by  DR.  E.  BARTOW.  Competitors  were  basswood 
plates  and  perforated  pipes.  (Cf.  Ref.  No.  310  and  367.) 

304  Apparatus  for  purifying  sewage,  etc.    LOCKETT  and  HERRING- SHAW.  Brit- 
ish patent  applications  11,561;  11,562,  Aug.  11,  1917.     Jour.  Soc.  Chem. 

Ind.  36,  Suppl.  79. 

55 


The  Activated  Sludge  Process 

305  Changes    in    Cleveland   sewage    plans.      ANON.      Eng.    News-Record   79, 
308-12.     Surveyor  52,  342.     Chem.  Abst.  11,  3358.     The  activated  sludge 

process  is  not  recommended  because  of  lack  of  funds,  because  sufficient  treat- 
ment for  some  time  to  come  should  be  afforded  by  screening,  chlorination,  and 
dispersion  of  the  sewage  into  the  lake  through  the  new  submerged  multiple 
outlet  pipe,  and  because  valuable  local  data  on  sludge  handling  may  be  expected 
in  the  near  future.  At  some  future  date  the  indications  are  that  the  activated 
sludge  process  should  be  considered  for  lake  shore  sites. 

306  Fine  screens  or  Imhoff  tanks?     EDITORIAL.     Eng.  News-Record  79,  290. 
A  consideration  of  the  different  recommendations  made  for  sewage  dis- 
posal at  Cleveland,  O.     The  activated  sludge  experiments  and  the  high  hopes 
expressed  for  this  process  are  referred  to. 

307  The  activated  sludge  process.    EDITORIAL.    Surveyor  52,  137-8.    Comment 
on  the  paper  by  DR.  E.  ARDERN    (Ref.  No.  296)   in  which  attention  is 

called  to  the  fact  that  sewage  in  most  American  cities  is  very  weak,  the  dry 
weather  flow  in  some  cases  amounting  to  60  to  120  gallons  per  head,  while  in 
English  cities  it  may  run  from  20  to  50  gallons  per  head.  Therefore,  figures 
given  as  to  cost  of  air  per  million  gallons  of  sewage  treated  in  the  two 
countries  are  very  apt  to  be  misleading,  and  the  suggestion  is  made  that  a 
safer  method  of  comparison  would  be  to  express  such  figures  in  terms  of  popu- 
lation, say  per  thousand  people. 

308  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  and 
JONES  &  ATTWOOD,  L'TD.,  Amblecote,  Eng.    British  Patent  122,428,  Aug. 

24,  1917.  Jour.  Soc.  Chem.  Ind.  38,  197 A.  Chem.  Abst.  13,  1734.  Sewage  is 
treated  with  bacterial  (activated)  sludge  and  the  mixture  agitated  by  the 
injection  of  air.  The  sludge  is  separated  continuously  or  intermittently  from 
the  liquid,  and  passed  to  another  tank  where  its  activity  is  intensified  by  the 
injection  of  air,  and  the  active  sludge  is  returned  to  the  treating  tank.  The 
separation  of  the  sludge  is  effected  in  a  series  of  tanks  so  arranged  that  the 
mixture  flows  through  them  at  varying  rates,  and  sludges  of  varying  specific 
gravity  are  separated  and  deposited  in  separate  sludge  pits  connected  with 
the  settling  tanks.  All  the  operations  form  a  continuous  cycle. 

309  Fertilizer.    G.  J.  FOWLER.     Danish  Patent  22,389,  Aug.  27,  1917.     Chem. 
Abst.  12,  512.     Air  is  blown  through  masses  obtained  in  the  purification 

of  sewage  in  the  presence  of  bacteria.  The  product  is  then  heated  and  dried, 
and  then  mixed  with  small  quantities  of  a  solid  containing  bacteria  beneficial 
to  plant  life,  so  that  the  final  product  contains  bacteria  favorable  to  plant 
growth  in  addition  to  large  quantities  of  nitrogen.  (Cf.  Brit.  Pat.  8,397,  Ref. 
No.  51;  U.  S.  Pat.  1,294,080,  Ref.  No.  454;  Can.  Pat.  189,921,  Ref.  No.  467.) 

310  Purification  of  sewage  by  aeration  in  the  presence  of  activated  sludge,  III. 
E.  BARTOW.    Jour.  Ind.  Eng.  Chem.  9,  845-50.    Jour.  Soc.  Chem.  Ind.  36, 

1146.  Jour.  Am.  Leather  Chem.  Assoc.  12,  563.  Trans.  Am.  Inst.  Chem.  Engrs. 
10,  159-75.  Chem.  Abst.  11,  3357.  Gives  further  results  obtained  at  the  sew- 
age experiment  station  of  the  111.  State  Water  Survey.  A  septic  tank  was 
reconstructed  into  an  activated  sludge  tank  to  handle  about  200,000  gallons  per 
day  on  the  continuous  flow  plan.  A  bar  screen  with  %  in.  openings  and  a 
two-compartment  grit  chamber  34  ft.  long  was  provided.  The  aerating  tank 
is  36l/2  ft.  by  17  ft.  by  9%  ft.  deep,  divided  by  3  baffles  into  4  compartments, 
thus  giving  the  sewage  a  flow  of  about  140  ft.  The  settling  chamber  is  10  Ms 
ft.  by  6  ft.  by  11  ft.  deep  with  sloping  walls,  and  provided  with  an  air  lift. 
Filtros  plates  supported  on  T-bars  embedded  in  concrete,  in  sets  of  6,  serve  as 
air  diffusers.  Aerating  periods  of  6,  5,  and  4  hours,  treating  144,000,  170,000, 
and  216,000  gallons  respectively,  with  settling  periods  of  24,  31,  and  37  minutes 
were  tried.  About  2  cu.  ft.  of  air  per  gallon  of  sewage  was  necessary  to  pro- 
duce a  stable  effluent.  Various  modifications  of  the  operating  details  were 
tried  and  the  results  given  in  the  tabulated  data.  For  comparing  different  air 

56 


Abstract  Bibliography — 1917 

diffusers  the  3  ft.  2  in.  square  by  8  ft.  deep  concrete  tanks  used  in  former 
experiments  were  employed.  (Ref.  No.  83.)  "A"  tank  was  fitted  with  per- 
forated pipes  having  1-25  in.  holes  spaced  2  in.  apart,  and  staggered  at  an 
angle  of  45  degrees  from  the  top  of  the  pipe.  "B"  tank  contained  basswood 
blocks  covering  an  area  of  1  ft.  3  9-16  in.  by  2  ft.  3  in.  "C"  tank  contained 
3  sq.  ft.  of  filtros  designated  as  "fine,"  and  "D"  tank  3  sq.  ft.  designated  as 
"coarse."  These  tanks  were  operated  during  three  periods  of  15,  20,  and  35 
days,  all  conditions  being  maintained  as  nearly  identical  as  possible.  The  re- 
sults obtained  from  these  comparative  tests  indicate  the  superiority  of  filtros, 
with  little  if  any  difference  between  the  two  grades.  In  the  sludge  dewatering 
experiments  drying  on  sand  beds  was  not  satisfactory,  nor  did  filter  pressing 
give  a  good  cake  even  with  a  fairly  concentrated  sludge.  The  Koering  rotary 
pressure  drum  filter  gave  unsatisfactory  results  on  the  first  trial,  further  tests 
being  prevented  by  an  accident.  Experiments  with  a  modified  basket  type  of 
centrifuge  and  a  cream  separator  were  encouraging,  but  a  specially  con- 
structed centrifuge,  designed  by  the  Tolhurst  Machine  Works,  gave  the  best 
results  and  indicated  that  a  large  machine  would  reduce  the  water  content  of 
the  sludge  to  about  88%.  Drying  tests  pointed  to  a  practical  way  of  dewater- 
ing further. 

311  Some  characteristics  of  the  activated  sludge  process  of  sewage  treatment. 

A.  L.  FALES.  Munic.  Engrg.  53,  108.  Can.  Engr.  33,  230.  A  general  dis- 
cussion of  the  process  giving  the  following  requisites  as  essential  for  the  suc- 
cessful treatment  of  sewage  by  this  process.  (1)  Correct  amount  of  bacterially 
active  sludge;  about  25%.  (2)  Supply  of  oxygen  to  promote  growth;  about 
1.75  cu.  ft.  of  air  per  gallon  of  sewage.  (3)  Proper  aeration  period;  about  4 
hours  for  ordinary  sewage.  (4)  Optimum  temperature  for  bacterial  action. 

312  Comparative  tests  of  air  diffusers  and  devices  for  dewatering  activated 
sludge.     ANON.     Eng.  &   Contg.   48,   217-20.     Can.   Engr.    33,   339-41. 

Chem.  Abst.  11,  3074.  Abstract  of  a  paper  by  DR.  E.  BARTOW  presented  at 
the  Buffalo  meeting  of  the  Am.  Inst.  Chem.  Engrs.  Filtros  plates,  perforated 
pipes  and  wood  blocks  were  tried,  filtros  proving  most  satisfactory.  Centri- 
fuges reduced  the  moisture  content  of  the  sludge  to  85-88%.  (Cf.  Ref.  Nos.  310 
and  367.) 

313  Jersey  City  water  supply  clean-up  proposed.     NEWS  ITEM.     Eng.  News- 
Record  79,  522.     Diversion  of  sewage  below  Boonton  dam  with  activated 

sludge  plant  and  chlorination  recommended. 

314  Apparatus  for  aerating  sewage.    GRIFFITHS  &  HARTLEY.    British  Patent 
Application  13,374,  Sept.  18,  1917.     Jour.  Soc.  Chem.  Ind.  36,  Suppl.  95. 

315  Activated  sludge  plant  proposed.    NEWS  ITEM.    Munic.  Jour.  43,  291.    To 
treat  the  sewage  discharged  into  the  Rockaway  river,  the  activated  sludge 

process  is  recommended  for  the  reasons  stated  by  G.  A.  JOHNSON,  that  the 
effluent  obtained  will  be  highly  satisfactory  as  far  as  physical  and  chemical 
characteristics  are  concerned.  Low  electric  power  cost  and  the  possibility  of 
disposing  of  the  sludge  at  a  profit,  justifies  its  adoption  on  economic  grounds. 

316  Brockton    (Mass.)    activated   sludge    plans.      NEWS    ITEM.     Eng.   News- 
Record  79,  551.    Plans  for  the  proposed  activated  sludge  plant  are  being 

made  by  H.  S.  CROCKER,  city  engineer,  but  will  probably  not  be  sufficiently 
advanced  for  bids  until  1918.  Plant  will  have  a  capacity  of  3  million  gallons 
daily,  with  a  4  hour  running-through  period. 

317  Fifty  million  gallon  plant  recommended  for  Chicago  stockyards.    EDITOR- 
IAL.   Surveyor  52,  253.     Abstract  of  a  pamphlet  issued  by  the  Sanitary 

District  of  Chicago  (Ref.  No.  271)  containing  the  report  and  recommendations 
of  RICHARDSON  and  PEARSE  for  a  50  million  g.  p.  d.  activated  sludge  plant  for 
Packingtown. 

57 


The  Activated  Sludge  Process 

318  The  treatment  of  trade  wastes.    EDITORIAL.    Surveyor  52,  246.    Mentions 
successful  experiments  for  treating  very  strong  packinghouse  wastes  at 

Fort  Worth,  Texas,  by  the  activated  sludge  process,  and  comments  on  the 
proposed  50  million  plant  at  the  Chicago  stockyards. 

319  Various  methods  of  de watering  activated  sludge.    DR.  E.  BARTOW.   Munic. 
Eng'rg.  53,  148-9.     Sand  beds,  filter  presses,  the  Koering  rotary  drum, 

and  centrifuges  were  considered.     (Cf.  Ref.  No.  310.) 

320  Experiments   on   sewage   purification   by   the   activated   sludge   process, 
A.   CRONIN.     Austral  Pharm.  Notes    (Oct.   1,  1917)    18-20.     Jour.  Soc. 

Chem.  Ind.  37,  106A.  Chem.  Abst.  12,  2033.  The  first  trial  was  made  at 
Sydney,  Aust.,  in  1916,  the  plant  consisting  of  3  wooden  tanks  of  500  gallons 
capacity  each,  air  being  supplied  through  perforated  pipes  covered  with 
broken  stone.  Two  of  the  tanks  were  seeded  with  sludge  from  contact  beds, 
but  this  method  proved  a  failure.  In  the  third  tank  raw  sewage  was  treated 
in  the  usual  way,  3  days  aeration  being  followed  by  15  hours  settling.  An- 
alyses made  after  2,  3,  and  4  months  working  gave  practically  concordant 
results,  the  purification  being  about  99%  in  suspended  solids,  92%  in  organic 
N,  and  84%  in  O  absorption.  All  the  effluents  were  stable  by  the  methylene 
blue  test  and  no  odor  was  given  off  during  treatment.  A  larger  tank  of 
10,000  gallons  capacity  was  then  constructed  of  concrete,  and  has  been  in 
continuous  operation  since  Nov.,  1916,  on  the  fill  and  draw  plan.  The  aera- 
tion period  at  starting  was  4  days,  then  3  days,  then  20,  10,  7,  6,  and  5  hours. 
After  8  weeks  the  accumulated  sludge  occupied  20-25%  of  the  capacity  of  the 
tank.  5  hours  aeration  did  not  give  good  results,  so  after  6  months  operation 
the  aerating  period  was  fixed  at  6  hours  with  2  hours  settling.  Purification 
was  96%  in  suspended  solids,  87.7%  in  organic  N,  and  86.3%  in  O  absorption. 
The  effluent  was  odorless  but  had  a  faint  "peaty  color,"  and  was  stable  after 
the  first  three  weeks  working.  Air  used  was  4.8  cu.  ft.  per  gallon  of  sewage. 
The  sludge  contained  66%  (?)  of  moisture  and  dried  readily  on  sand.  An 
analysis  calculated  to  10%  moisture  showed  total  N,  3.2%;  phosphoric  acid, 
2.7%;  potash,  0.35%. 

321  Comparative  tests  of  air  diffusers.     ANON.    Surveyor  52,  528.     The  re- 
sults of  competitive  tests  of  wood  blocks,  perforated  pipes  and  filtros 

plates,  indicated  the  superiority  of  the  latter.  From  DR.  E.  BARTOW'S  paper, 
reference  No.  310. 

322  Activated  sludge  process  for  the  Stockyards.     ANON.    Munic.  Jour.  43, 
377-9.    Digest  of  the  report  of  PEARSE  and  RICHARDSON  on  the  proposed 

activated  sludge  plant  for  treating  packinghouse  wastes.     (Cf.  Ref.  No.  271). 

323  Machinery  in  sewage  treatment.    EDITORIAL.  Munic.  Jour.  43,  381.   Com- 
ments on  the  report  of  PEARSE  and  RICHARDSON  on  the  50  million  gallon 

plant  proposed  at  Chicago,  and  points  out  the  large  amount  of  machinery 
required  in  the  activated  sludge  process  as  compared  with  other  methods,  as 
well  as  the  skill  required  for  its  operation. 

324  Removal  of  activated  sludge.    T.  C.  HATTON.   Munic.  Jour.  43,  382.    Sur- 
veyor 52,  445.     A  Dorr  thickener  was  used  in  a  13  ft.  diam.  tank,  re- 
moving the  sludge  continuously  to  a  central  draw-off,  and  promises  to  be 
successful.    The  sludge  is  prevented  fiom  settling  on  the  slopes  of  the  hopper 
bottom  and  becoming  septic. 

325  Preliminary  treatment  of  sewage:  fine  screens.    EDITORIAL.   Surveyor  52, 
333.     It  is  mentioned  that  the  activated  sludge  process  was  given  due 

consideration  at  Cleveland,  O.,  but  was  rejected  as  not  suitable  under  present 
existing  conditions. 

58 


Abstract  Bibliography — 1917 

326  Notes  on  activated  sludge  with  particular  reference  to  the  treatment  of 
packinghouse  wastes.    LANGDON  PEARSE.     Can.  Engr.  33,  358-9.    A  paper 

presented  at  the  meeting  of  the  Am.  Pub.  Health  Assoc.  on  Oct.  18,  1917. 
The  sewage  testing  station  of  the  Chicago  Sanitary  District  is  described,  and 
the  results  obtained  up  to  March,  1917,  show  that  the  sewage  should  be 
screened  through  30  mesh,  as  it  will  then  by  8  hours  aeration  produce  a  stable 
effluent  in  summer  with  4  cu.  ft.  of  air  per  gallon,  in  tanks  16.5  ft.  deep. 
6  cu.  ft.  of  air  or  more,  may  be  required  in  cold  weather  to  produce  equivalent 
stability.  Air  distribution  was  through  filtros  plates  set  in  cast-iron  boxes; 
ratio,  1  to  6.  Recoveries  per  million  gallons  of  sewage  were  as  follows: — 
Grease  as  scum,  360  Ibs.;  as  grease,  47  Ibs.;  screenings,  dry  basis,  600-1000 
Ibs.;  sludge,  dry  basis,  2000-3000  Ibs.  Requirements  for  Fort  Worth,  Texas, 
packinghouse  sewage  plants  are  compared  with  those  for  Chicago.  The  ar- 
rangement and  design  of  the  tanks;  methods  of  baffling,  agitation,  and  air 
distribution;  sludge  settling  and  treatment,  touching  on  the  effect  of  acid  on 
activated  sludge  from  different  sources;  and  stability  of  effluent  are  consid- 
ered. The  plants  herein  referred  to  have  been  remarkably  free  from  odor. 
Typical  analyses  of  sewage,  screenings,  and  sludge  are  given,  and  the  author 
expresses  the  opinion  that  the  activated  sludge  process  offers  the  best  promise 
of  treating  packinghouse  wastes,  and  recommends  a  unit  plant  of  1.5  million 
gallons  daily  capacity,  so  as  to  obtain  large-scale  working  results.  (Cf.  Ref. 
Nos.  271,  327,  337  and  371). 

327  Activated  sludge  to  solve  packinghouse  wastes  problem.  LANGDON  PEARSE. 
Eng.  News-Record  79,  777-8.     Chem.  Abst.  12,  75.     At  Chicago,  4  cu. 

ft  of  air  per  gallon  of  sewage  in  summer,  and  6  cu.  ft.  in  winter,  is  sufficient 
to  stabilize  the  effluent.  Filtros  plates  appears  to  be  the  best  material  for 
air  diffusion,  though  perforated  pipes  were  tried  but  they  required  more  air. 
The  ratio  of  gross  area  of  filtros  plates  to  tank  area  at  Chicago  was  1  to  6.3 ; 
net  area  1  to  8.  At  Fort  Worth,  Texas,  1  to  7  has  been  used.  Settling 
period  may  be  0.5  to  1  hour,  and  bottom  slopes  should  be  60  degrees  from  the 
horizontal.  Velocities  should  be  low.  For  9  months,  with  screened  sewage, 
about  46,500  gallons  of  liquid  sludge  having  99.2%  water,  was  obtained  per  mil- 
lion gallons  of  sewage,  which  is  equivalent  to  2,420  Ibs.  of  dry  solids.  The 
screenings,  on  30  mesh,  varied  from  500  to  1,200  Ibs.  of  dry  material.  Plain  sedi- 
mentation reduces  considerably  the  moisture  content  of  the  sludge,  which 
contains  on  a  dry  basis  from  5  to  6%  N,  with  an  estimated  value  of  $12 
to  $18  per  ton.  (Cf.  Ref.  Nos.  271,  326,  337  and  371). 

328  The  treatment  of  sewage  by  aeration  and  activated  sludge.  ANON.  Engin- 
eering 104,  444.     Chem.  Abst.  12,  1224.     Comments  on  efficient  air  dif- 
fusion and  aeration;  the  progress  of  the  activated  sludge  work  in  America, 
with  special  reference  to  Milwaukee;   the  work  at   Sheffield,   Eng.;    and   on 
DR.  E.  ARDERN'S  paper.     (Ref.  No.  296).     Operating  costs  and  sludge  treat- 
ment are  discussed,  including  the  DICKSON  yeast  process  of  dewatering. 

329  New  Haven  (Conn.)  tests  five  processes  of  sewage  treatment.     F.  W. 
MOHLMAN.     Eng.  News-Record  79,  829-30.     Engineer  125,  97.     Respect- 
ing the  activated  sludge  process,  the  experiments  were  carried   out  on  the 
continuous  flow  plan  in  tanks  16  ft.  by  4  ft.  by  8  ft.  deep,  with  filtros  plates 
set  in  cast-iron  frames  as  the  air  diffusers.     17,000  gallons  are  treated  daily, 
allowing  3  hours  for  aeration  and  66  minutes  for  settling.     (Cf.  Ref.  No.  338). 

330  Sewage  purification.    L.  G.  B.  requirements  and  other  data.   S.  H.  ADAMS. 
Pamphlet  pp.  6.     (Nov.  1917).     A  brief  general  description  of  the  acti- 
vated sludge  process,  and  some  data  from  the  Milwaukee  experiments,  occupy 
one  page. 

331  How  the  activated  sludge  process  of  sewage  disposal  is  working  in  Pas- 
adena.    R.  V.  ORBISON.     Pacific  Municipalities  (Nov.  1917)   594-606.     A 

description  of  the  testing  station,  the  process,  and  a  brief  summary  of  the 
results  obtained.  Treatment  cost  estimates  and  a  consideration  of  the  pos- 
sible revenues  from  the  process  are  given.  (Cf.  Ref.  349). 

59 


The  Activated  Sludge  Process 

332  Clearing  house  summary  on  activated  sludge.     EDITORIAL.     Eng.  News- 
Record  79,  817.    Comment  on  T.  C.  HATTON'S  paper.    (Ref.  No.  333).  "In 

a  large  sense,  Milwaukee  has  been  a  clearing  house  for  activated  sludge 
data  and  opinion,  for  nearly  everyone  interested  in  the  process  has  visited 
the  Milwaukee  testing  station  or  at  least  has  corresponded  with  Mr.  Hatton. 
— The  initial  work  at  Lawrence  and  its  elaboration  by  DR.  GILBERT  J.  FOWLER 
and  his  followers  in  England,  should  never  be  lost  sight  of  by  those  who 
desire  to  give  credit  where  credit  is  due." 

333  Conclusions  on  the  activated  sludge  process  at  Milwaukee,  Wis.     T.  C. 

HATTON.  Eng.  News-Record  79,  840-4.  Surveyor  53,  232-3,  254-5.  Chem. 
Abst.  12,  75.  Mr.  Hatton's  paper  before  the  Am.  Public  Health  Association  in 
October,  1917.  When  sewage  is  treated  1  hour  with  0.5  cu.  ft.  of  air  per 
gallon  in  an  aerating  tank  of  15  ft.  effective  depth,  a  98%  removal  of  sus- 
pended matter  is  obtained,  but  for  complete  nitrification  0.75  to  1.1  cu.  ft. 
of  air  per  gallon  must  be  applied  4  to  6  hours.  To  prevent  clogging  of  the 
air  diffusing  plates,  grit  chamber  treatment  is  necessary  when  storm  water 
is  mixed  with  the  sewage,  and  preliminary  treatment  with  fine  screens  is 
recommended  for  sewage  from  industrial  communities,  while  for  purely  do- 
mestic sewage,  3-16  in.  slotted  screen  is  sufficient.  About  20%  of  well 
activated  sludge  is  necessary  for  satisfactory  treatment.  The  sludge  as 
withdrawn  from  the  aerating  tanks  contains  99  to  99.5%  water,  which  is 
reduced  to  96%  by  5  to  6  hours  settling.  Presses  and  driers  can  be  used 
to  lower  the  water  content  to  10%.  Typical  analysis  of  dried  sludge  shows 
5.1%  ammonia,  5.3%  fat,  0.5%  soluble  phosphorus  pentoxide,  and  0.25%  potas- 
sium oxide.  Flies,  insects,  and  worms  do  not  infest  the  treatment  plant,  nor 
is  any  offensive  odor  connected  with  the  process. 

334  The  activated  sludge  method  of  sewage  treatment.     F.  W.  MOHLMAN. 
Univ.  Ill  Bull  15,  75-113.     (Water  Survey  Series  No.  14).    Abst.  Bact.  2, 

149.  Pamphlet  pp.  43.  "1.  In  the  aeration  of  sewage  there  is  almost  quan- 
titative oxidation  of  ammonia  N  to  nitrite  N,  followed  by  oxidation  to  nitrate 
N.  From  10  to  20  days  are  required.  In  the  aeration  of  sewage  in  contact 
with  activated  sludge,  ammonia  N  is  oxidized  to  nitrate  N  in  from  4  to  5 
hours.  Nitrite  N  is  evidently  oxidized  to  nitrate  N  almost  as  rapidly  as  it  is 
formed.  2.  Satisfactory  activated  sludge  can  be  obtained  with  6  hour  aera- 
tion periods  without  complete  nitrification  from  the  beginning  of  the  opera- 
tion. 3.  In  a  small  tank  the  equivalent  of  1,300  Ibs.  of  dry  sludge  per  million 
gallons  of  strong  sewage  was  obtained.  In  larger  tanks  740  to  1,150  Ibs.  of 
dry  sludge  per  million  gallons  of  average  sewage  were  obtained.  4.  In  the 
presence  of  25%  sludge,  weak  sewage  was  well  nitrified  in  4  hours  with  1 
cu.  ft.  of  air  per  gallon  of  sewage.  Normal  sewage  required  4-5  hours  aeration 
and  1.3  cu.  ft.  of  air  per  gallon  of  sewage.  Strong  sewage  required  more  than  5 
hours  aeration  and  more  than  1.5  cu.  ft.  of  air  per  gallon  of  sewage.  5.  Better 
results  were  obtained  when  1-3  the  floor  surface  was  covered  with  porous 
plates,  than  when  all  or  1-9  of  the  floor  surface  was  covered.  6.  The  N  in 
the  sludge  increases  by  from  0.5  to  1.5%  per  day  until  an  average  of  5.1% 
N  is  obtained.  7.  The  content  of  phosphoric  pentoxide  varies  in  the  same 
way  as  the  N,  reaching  an  average  of  about  3%.  8.  Dewatering  the  sludge  is 
a  problem  which  has  not  yet  reached  a  satisfactory  solution,  although  small 
scale  experiments  with  centrifuges  have  given  promising  results.  It  has 
been  practically  impossible  to  obtain  a  solid  cake  by  filter-pressing  the  acti- 
vated sludge  and  experiments  with  precipitants  and  filtros-plate  filters  also 
gave  unsatisfactory  results."  The  above  is  the  author's  summary  of  the 
article. 

335  Decomposition  products  of  sewage  disposal.    F.  N.  CRAWFORD.    Univ.  III. 
Bull.  15,  162-8.     (Water  Survey  Series  No.  14).     Abst.  Bact.  2,  149.     A 

study  of  the  effluent  gases  in  the  activated  sludge  process.  Author's  con- 
clusions:— "Aeration  of  tap  water,  of  sewage,  and  of  sewage  in  the  presence 
of  activated  sludge,  yield  quantities  of  carbon  dioxide  and  of  O  which  are 

60 


Abstract  Bibliography — 1917 

greatly  at  variance.  (1)  Tap  water  containing  bicarbonates,  when  aerated 
undergoes  a  loss  of  carbon  dioxide,  the  partial  conversion  of  bicarbonates 
to  normal  carbonates,  and  the  establishment  of  dissolved  0  at  the  normal 
for  water  saturated  with  atmospheric  gases.  (2)  Sewage  alone  undergoes 
similar  changes;  the  extinction  of  free  carbon  dioxide;  partial  conversion  of 
bicarbonates  to  normal  carbonates,  and  dissolved  O  slightly  less  than  the  nor- 
mal for  air-saturated  water.  (3)  Sewage  with  activated  sludge  similarly 
aerated  yields  increasing  quantities  of  carbon  dioxide  as  the  sludge  builds  up, 
while  the  bicarbonate  alkalinity  remains  unchanged.  The  increment  of  carbon 
dioxide  appearing  in  the  effluent  gases  collected  during  aeration  of  the  sew- 
age with  activated  sludge  is  derived  from  biological  fermentation  of  car- 
bonaceous matter."  (Cf.  Ref.  158). 

336  Bacterial  purification  of  sewage.    W.  F.  KAMM.   Univ.  III.  Bull.  15,  146-61. 

(Water  Survey  Series  No.  14).  Chem.  Abst.  12,  1674.  Abst.  Bact.  2, 
149.  Conclusions: — "(a)  Denitrifying  bacteria  reduce  the  nitrate  and  nitrite 
in  sewage,  (b)  They  are  constantly  present  in  sewage,  but  their  action  is 
often  overlooked  because  of  the  greater  amount  of  nitrification,  (c)  In  all 
the  aeration  experiments  a  large  amount  of  N  (as  ammonia)  is  lost,  (d) 
The  denitrifying  action  (under  certain  conditions)  predominates  over  the 
nitrifying  action  and  may  be  the  cause  of  the  failure  to  nitrify  the  sewage 
in  some  aeration  tanks,  (e)  Denitrifying  organisms  play  an  essential  role 
in  the  purification  of  sewage  by  aeration  in  the  presence  of  activated  sludge." 
Numerous  diagrams  accompany  the  article. 

337  The  treatment  of  packinghouse  wastes  by  the  activated  sludge  process. 

ANON.  Eng.  &  Contg.  48,  386-8.  Practically  the  full  paper  presented 
by  LANGDON  PEARSE  at  the  meeting  of  the  Am.  Public  Health  Assoc.  on  Oct. 
18,  1917.  (Cf.  Ref.  Nos.  271,  326,  327  and  371). 

338  The  sewage  experiment  station  at  New  Haven,  Conn.     ANON.    Eng.  & 
Contg.  48,  390-1.     The  activated  sludge  experiments  were  on  the  con- 
tinuous flow  plan  in  an  aerating  tank  16  by  4  by  8  ft.  deep,  with  a  bottom 
sloping  at  45  degrees  to  a  trough  1  ft.  wide,  in  which  were  placed  15  filtros 
plates  as  air  diffusers.     The  settling  tank  is  4  by  4  by  12  ft.  deep  to  the 
bottom  of  the  hopper.     Aerating  tank  has  a  capacity  of  3,100  gallons  and  is 
treating  17,000  gallons  of  sewage  daily  with  a  3  hour  aeration  period.    Settling 
tank  has  a  capacity  of  1,150  gallons,  and  the  settling  period  is  66  minutes. 
(Cf.  Ref.  329). 

339  Papers  on  activated  sludge.     NEWS  ITEM.    Eng.  News-Record  79,  940. 
Refers  to  reprints  of  papers  by  DR.  E.   ARDERN  which  are  available. 

These  reprints  cover  articles  noted  in  Ref.  Nos.  244  and  296. 

340  Nature  of  activated  sludge.     F.   DIENERT.     Comptes  rend.   165,  1116-7. 
Jour.  Soc.  Chem.  Ind.  37,  71  A.     Chem.  Abst.  12,  1224.     To  prepare  acti- 
vated sludge  from  Paris  sewage  it  was  found  necessary  to  aerate  the  sewage 
for  30  hours  to  effect  nitrification  of  the  10   mgrs.   of   ammonia   per   liter 
which  it  contained.    The  liquid  was  then  decanted,  a  further  volume  of  sewage 
admitted  to  the  residual  sludge,  and   aeration  continued.     These   operations 
were  repeated  for  15  to  20  days,  when  the  time  required  for  nitrification  had 
been  reduced  to  1.5  hours,  and  the  volume  of  the  sludge  had  much  increased. 
During  the  aeration  the  dissolved  carbon  dioxide  is  expelled  and  the  calcium 
bicarbonate  precipitated  as  carbonate;   at  the  same  time  the  precipitate  re- 
moves some  of  the   suspended   and   dissolved   organic  matter  by  absorption. 
It  was  found  that  the  alkalinity  of  the  sewage  was  reduced  from  180  to  60 
parts  of  lime  per  million,  by  1.5  hours  aeration.     The  activated  sludge  con- 
tained  50%   mineral  matter,  chiefly  calcium  carbonate;    20%   of   albuminoid 
matter,  and  30%  of  non-albuminoid  matter.     In  tests  in  which  the  sewage 
took  2  hours  to  travel  along  the  sewers,  it  was  found  that  in  consequence  of 
the  aeration  which  took  place  during  that  time,  that  about  three-quarters  of 
the  albuminoid  and  ammoniacal  matter  was  absorbed  by  the  precipitated  cal- 
cium carbonate,  and  was  found  in  the  deposits  of  same  along  the  sewers. 

61 


The  Activated  Sludge  Process 

341  Purification  of  sewage  and  analogous  liquids.     W.  JONES,   Stourbridge, 
Eng.   U.  S.  Patent  1,247,540,  Nov.  20,  1917.  (Application  filed  Oct.  9,  1914. 

16  claims).  Off.  Gaz.  244,  774.  Jour.  Soc.  Chem.  Ind.  37,  38A.  Chem.  Abst.  12, 
397.  Claim  3 : — The  process  of  treating  sewage  or  the  like,  consisting  in 
causing  a  local  upflow  in  the  liquid,  and  supplying  air  locally  into  the  liquid 
in  its  flow;  causing  the  sludge  and  solid  matters  to  pass  to  a  point  of  the 
part  of  the  flow  which  is  being  supplied  with  air;  and  removing  the  clarified 
liquid  from  the  body.  Claim  5: — The  process  of  treating  sewage  or  the 
like,  consisting  in  causing  an  up  and  down  flow,  and  a  lateral  flow  in  the 
liquid,  the  lateral  flow  being  from  the  upper  part  of  the  upflowing  part  of 
the  liquid,  and  supplying  air  into  the  liquid  in  its  flow.  (Cf.  Brit.  Pat.  22,952. 
Ref.  No.  3). 

342  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  Eng. 
U.    S.    Patent   1,247,541,   Nov.   20,    1917.      (Application   filed    Sept.    13, 

1915.  6  claims).  Off.  Gaz.  244,  774.  Jour.  Soc.  Chem.  Ind.  37,  38A.  Chem. 
Abst.  12,  397.  Claim  1: — The  process  of  purifying  sewage  or  other  impure 
liquid  by  supplying  the  sewage  or  impure  liquid  to  a  tank,  supplying  or  de- 
livering air  in  small  bubbles  periodically  a  plurality  of  times  at  different  points 
to  the  liquid  in  the  tank  during  its  treatment,  until  it  is  purified,  and  run- 
ning off  the  purified  liquid.  (Cf.  Brit.  Pat.  1,141,  Ref.  No.  33  and  Can.  Pat. 
183,586,  Ref.  No.  402). 

343  Purification  of  sewage  and  analogous  liquids.     W.  JONES,  Stourbridge, 
Eng.    U.  S.  Patent  1,247,542,  Nov.  20,  1917.     (Application  filed  Oct.  18, 

1915.  9  claims).  Off.  Gaz.  244,  774.  Jour.  Soc.  Chem.  Ind.  37,  38A.  Chem. 
Abst.  12,  397.  Claim  4: — The  process  of  purifying  sewage  or  analogous 
liquids,  consisting  in  supplying  crude  sewage  or  liquid,  causing  it  to  flow 
while  being  treated,  delivering  air  into  the  liquid  in  the  presence  of  bacterial 
sludge  or  solid  matter,  depositing  the  sludge  at  a  point  of  its  flow  removed 
from  that  where  the  aeration  or  oxidation  is  taking  place,  and  transferring 
the  deposited  sludge  or  solid  matters  to  the  sewage  or  liquid  in  the  aerating 
or  oxidizing  portion.  (Cf.  Brit.  Pat.  22,737,  Ref.  No.  18). 

344  Purification  of  sewage  and  analogous  liquids.     W.  JONES,   Stourbridge, 
Eng.    U.  S.  Patent  1,247,543,  Nov.  20,  1917.     (Application  filed  Oct.  18, 

1915.  6  claims).  Off.  Gaz.  244,  775.  Jour.  Soc.  Chem.  Ind.  37,  38A.  Chem. 
Abst.  12,  397.  Claim  5: — The  process  of  purifying  sewage  or  analogous 
liquids,  which  consists  in  aerating  or  oxidizing  a  plurality  of  quantities  of 
liquid  in  the  presence  of  bacterial  sludge,  depositing  sludge  or  solid  matters 
therefrom,  transferring  the  sludge  in  which  the  bacteria  have  deteriorated  or 
weakened  to  tanks,  aerating  or  oxidizing  the  removed  and  debilitated  sludge 
and  so  recuperating  it,  and  transferring  the  recuperated  sludge  to  one  or 
more  of  the  bodies  of  the  liquid  being  treated.  (Cf.  Brit.  Pat.  22,736.  Ref. 
No.  17). 

345  Handling  sludge  from  activated  plants.     ANON.    Munic.  Jour.  43,  508. 
Conclusions   from   operation   of   the   test  plants   at   Chicago   and    Fort 

Worth,  Texas.  Acid  acts  differently  on  the  two  sludges.  Plain  settling  has 
considerable  value  in  reducing  moisture  content,  but  effectiveness  varies  with 
the  condition  of  the  sludge.  Improvements  in  settling  tanks,  other  devices 
as  the  Dorr  tank,  the  use  of  coagulents,  filter  pressing,  etc.,  should  be 
studied  with  a  view  of  more  effectively  reducing  the  water  content  of  acti- 
vated sludge. 

346  Sewage  disposal  for  Indianapolis,  Ind.    ANON.   Munic.  Jour.  43,  510.    A 
report  on  the  application  of  modern  methods  of  sewage  treatment  to 

the  conditions  at  Indianapolis,  made  by  G.  W.  FULLER  to  the  sanitary  com- 
mission of  that  city,  considers  in  some  detail  the  Imhoff  tank,  the  activated 
sludge,  and  the  fine  screen  methods  of  treatment,  concluding  in  favor  of 

62 


Abstract  Bibliography — 1917 

the  last.  The  report  refers  to  the  large  installations  of  Imhoff  tanks  and 
their  difficulties,  and  to  the  large  experimental  activated  sludge  plants,  but 
is  not  encouraging  as  to  the  efficiency  of  either.  (Cf.  Ref.  No.  347). 

347  Screens,  filters  and  humus  tanks  for  Indianapolis,  Ind.     ANON.      Eng. 
News-Record  79,  972-4.     Chem.  Abst.  12,  395.     This  method  of  sewage 

treatment  has  been  recommended  by  G.  W.  FULLER  after  considering  also, 
Imhoff  tanks  with  sprinkling  filter,  and  the  activated  sludge  process.  It  is 
stated,  however,  that  the  activated  sludge  process  is  the  cheapest  one  to 
install  and  that  it  would  produce  the  most  complete  purification,  but  in  com- 
paring its  status  at  Indianapolis  with  its  suitability  elsewhere,  recognition 
should  be  given  to  the  fact  that  there  would  be  no  saving  in  the  purchase 
of  site  or  in  construction  of  intercepting  or  outfall  sewers  by  locating  this 
compact  type  of  plant  nearer  the  city.  (Cf.  Ref.  No.  346). 

348  Many  activated  sludge  plants.    NEWS  ITEM.   Eng.  News-Record  79,  987. 
About  25  experimental  activated  sludge  plants  have  been  built  in  vari- 
ous parts  of  the  world,  according  to  a  paper  read  recently  by  MR.  T.  C.  HAT- 
TON  before  the  Am.   Pub.  Health  Assoc.     Of  these  one  was  in  India,   7  in 
England,  and  14  in  the  United  States.     Seven  treatment  plants  have  been 
built  in  the  United  States,  and  4  more  of  considerable  magnitude  are  pro- 
posed. 

349  Activated  sludge  tests  made  by  California  cities.     ANON.    Eng.  News- 
Record  79,  1009-10.     Chem.  Abst.  12,  395.     Description  of  experimental 

plant  and  result  of  tests  made  at  Pasadena,  Calif.,  under  the  direction  of 
R.  V.  ORBISON.  The  aerating  tank  is  20  by  9  by  10  ft.  deep,  with  two  length- 
wise partitions  giving  a  60  ft.  continuous  channel,  in  which  21  filtros  plates 
are  located.  Ratio  1  to  8.5.  Two  settling  tanks  were  built  but  only  one 
used.  A  sludge  reaerating  tank  12  by  6  at  the  top,  12  by  2  at  the  bottom, 
and  10  ft.  deep,  equipped  with  4  filtros  plates  is  in  use.  4  hours  aeration 
using  1  cu.  ft.  of  air  per  gallon  of  sewage,  with  10-20%  activated  sludge, 
followed  by  30  minutes  settling,  gives  a  non-putrescible  effluent,  containing 
nitrates,  and  a  bacterial  reduction  of  96  to  99.6%.  Other  aeration  periods 
and  air  volumes  were  tried.  Sludge  drying  in  open  beds  gives  rise  to  odors 
that  make  this  means  impossible.  The  daily  flow  from  the  3  cities  interested 
(Pasadena,  South  Pasadena  and  Alhambra)  is  about  3  million  gallons,  nor- 
mal; 7.5  million  gallons,  maximum.  Testing  plant  handles  50,000  gallons 
daily  on  an  area  of  267  sq.  ft.,  or  the  equivalent  of  8  million  gallons  per  acre 
on  a  4  hour  aeration  basis.  It  is  estimated  that  the  activated  sludge  process 
would  save  at  least  50%  on  the  construction  cost  of  Imhoff  tanks  with  neces- 
sary accessories.  (Cf.  Ref.  No.  331). 

350  Activated  sludge.     THOS.   CAINK.     Surveyor  52,   471.     In  a  communi- 
cation to  the  editor  it  is  stated  that  because  of  its  buoyant  nature,  the 

sludge  will  not  flow  down  sloping  sides.  Scrapers  on  flat-bottom  tanks  were 
first  recommended  by  the  author  in  his  paper  in  The  Surveyor  52,  51-2.  July 
20,  1917.  (Ref.  No.  295). 

351  Worcester,  (Mass.)  activated  sludge  experiments.    M.  GAULT.    Ann.  Re- 
port. Supt.  Sewers  for  year  ending  Nov.  30,  1917.     697-731.     Refers  to 

the  100,000  gallons  experimental  activated  sludge  plant  which  begun  opera- 
tions July  7,  1917.  Results  to  be  reported  when  experiments  are  completed. 
(Cf.  Ref.  No.  487  and  540). 

352  Sewage  disposal  in  Kansas.     F.  M.  VEATCH,  H.  P.  EVANS  and  L.  E. 
JACKSON.     Bull.  Univ.  of  Kansas,  18,  30.    A  brief  general  description  of 

the  activated  sludge  process  is  given. 

353  Some  conclusions  reached  at  Milwaukee  on  the  treatment  of  sewage  by 
the  activated  sludge  process.    ANON.     Munic.  Eng'rg.  53,  243-6.    Results 

63 


The  Activated  Sludge  Process 

of  observations  and  studies  of  operation  of  the  sewage  testing  station.  From 
a  paper  by  T.  C.  HATTON  presented  at  a  meeting  of  the  Am.  Public  Health 
Assoc.  (Cf.  Ref.  No.  333). 

354  Copper  in  sewage  at  New  Haven  Experiment  Station.    F.  W.  MOHLMAN. 
Jour.  Ind.  Eng.  Chem.  9,  1093-6.     Refers  to  the  activated  sludge  plant 

and  experiments  as  in  references  Nos.  329  and  338. 

355  Pressing  sewage  sludge.    ANON.   Can.  Engr.  33,  473-4.    Munic.  Jour.  44, 
14-6.     Eng.  &  Contg.  49,  165-8.     Chem.  Abst.  12,  842.     Abridgement  of 

a  paper  by  KENNETH  ALLEN  read  at  the  1917  meeting  of  the  Am.  Soc.  Munic. 
Impvts.,  in  which  activated  sludge  is  referred  to  only  as  in  reference  No.  365. 

356  Are  fine  screens  needed  for  the  activated  sludge  process?    G.  B.  GASCOIGNE 
and  T.  C.  HATTON.     Eng.  News-Record  79,  1072-3.     Letters  to  the  editor 

in  which  the  first  author  questions  the  necessity  for  fine  screens  as  prelimin- 
ary to  the  activated  sludge  process:  answered  by  the  second  author  to  the 
effect  that  they  insure  a  more  satisfactory  operation  of  the  plant.  Essentially 
a  discussion  as  to  the  merits  of  coarse  and  fine  screens  at  Cleveland  and 
Milwaukee  respectively. 

357  Cleveland  sewage  screen  plans  withdrawn  from  State  Dept.  of  Health. 

ANON  Eng.  News-Record  79,  1128.  City  will  submit  plans  for  screens 
and  activated  sludge  plant,  and  request  that  construction  of  the  latter  be 
postponed  until  screens  have  been  operated  for  one  year. 

358  California  sewage  plants  are  neglected.     ANON.    Eng.  News-Record  79, 
1127.     Refers  to  sewage  plants  in  general  but  notes  that  the  new  acti- 
vated sludge  plant  at  the  Folsom  state  prison  has  recently  been  put  into  opera- 
tion to  handle  the  sewage  produced  by  1,500  inmates.     Ordinary  objections  to 
power  costs  do  not  pertain  here  as  the  prison  generates  its  own  power.     (Cf. 
Ref.  No.  567.) 

359  The  real  issue  as  to  sewage  plans  at  Cleveland.    EDITORIAL.    Eng.  News- 
Record  79,   1085.     Intimates  that  the  local   conditions  may  compel  the 

city  to  treat  its  sewage  by  activated  sludge  process. 

360  Activated    sludge    system    of    sewage    purification    at    Worcester,    Eng. 

ANON.  Sanitary  Record  59,  393.  Chem.  Abst.  11,  3357.  The  cost  of 
power  for  aerating  sewage  and  sludge  is  32s  per  million  gallons,  when  the  rate 
is  750,000  gallons  per  day.  Average  analyses  of  12  samples  of  effluent,  cover- 
ing a  12-month  period  was: — Suspended  matter  7.2;  albuminoid  ammonia,  1.4; 
O  absorbed  in  4  hours,  5.6  p.  p.  m.  Porous  tile  seems  to  diffuse  the  air  better 
than  mechanical  diffusers.  A  reduction  of  50%  of  the  air  used  is  obtained  by 
the  use  of  a  patent  pulsating  gear  (Ref.  No.  33)  which  supplies  the  air  in 

?uffs,  resulting  in  better  circulation.     Experiments  with  activated  sludge  as 
ertilizer  showed  an  increased  yield  of  potatoes  of  100%  over  those  to  which 
barnyard  manure  was  applied. 

361  The  activated  sludge  process.     EDITORIAL.    Surveyor  52,  527.     Comment 
on  DR.  E.  BARTOW'S  article  on  air  diffusers  (Ref.  No.  321)  in  which  it  is 

noted  that  porous  tile  diffusers  are  more  satisfactory  in  America  as  well  as 
in  England. 

362  Investigations   in   regard   to   purification   of   sewage   and   water   at  the 
Lawrence  experiment  station  during  the  year  1917.    H.  W.  CLARK.    3rd. 

Ann.  Report  State  Dept.  of  Health,  Mass.  122-72.  Munic.  Jour.  Pub.  Works 
47,  345-6.  Chem.  Abst.  14,  1174.  During  1917  the  tanks  containing  layers  of 
slate  remained  in  operation,  and  new  and  larger  activated  sludge  tanks  were 
started.  Briefly  summarizing  the  extensive  studies,  it  may  be  noted  that 
sewage  of  different  characters  and  strengths  require  very  different  aerating 

64 


A bstract  Bibliography — 1 91 7 

periods  and  air  volumes  for  satisfactory  results,  and  unless  these  are  employed 
in  excess,  a  modified,  rather  than  a  purified  sewage  results.  The  quality  of 
the  sludge,  physically  and  chemically,  appears  to  be  of  vital  importance,  and 
too  much  can  be  used.  In  certain  experiments  the  amount  of  O  required  for 
sewage  oxidation  was  found  to  be  350  pounds  per  million  gallons,  whereas- 
activated  sludge  at  2  cu.  ft.  of  air  per  gallon,  required  100  times  this  amount 
to  stability.  Studies  on  the  destruction  of  organic  matter  by  oxidation;  the 
effect  of  sterilizing  chemicals  on  activated  sludge;  (mercuric  chloride  stops  its 
action  completely)  and  of  the  progressive  flow  through  activated  sludge  and 
other  tanks  (Ref.  No.  434)  are  noted  in  this  report,  as  well  as  numerous  tables 
of  analytical  data. 

363  Syracuse,  N.  Y.,  tests  two  methods  of  sewage  treatment.     ANON.     Eng. 
News-Record  79,  1201-2.  Chem.  Abst.  12,  730.  The  activated  sludge  in- 
stallation embraces  an  aerating  tank  12  by  4  by  10  ft.  deep,  and  1  inch  pipes 
with  1-16  inch  perforations  3  inches  center  to  center,  distributes  the  air.     Set- 
tling tank  is  4  ft.  square,  maximum  dentil  15  ft.,  with  4  to  1  sloping  bottom. 
From  this  tank  an  air  lift  delivers  the  sludge  back  to  the  aerating  tank  or  to  a 
sludge  re-aerating  tank,  also  4  ft.  square.     (Cf.  Ref.  No.  378.) 

364  The  disposal  of  sludge.    DISCUSSION.    Surveyor  52,  552-3.    Various  prac- 
tices are  discussed  at  the  annual  meeting  of  Mgrs.  of  Sewage  Disposal 

Works.  Mention  is  made  of  the  fine  screens  used  successfully  at  the  Milwaukee 
activated  sludge  plant. 

365  The  pressing  of  sewage  sludge.     K.  ALLEN.     Trans.  Am.  Soc.  Munic. 
Impvts.  24,  1-25.    A  tabulation  of  the  properties  and  quantities  p.  m.  g. 

of  the  various  sludges  is  given,  including  activated  sludge.  The  Berrigan  or 
Worthington  press  at  Milwaukee,  with  activated  sludge,  reaches  an  ultimate 
pressure  of  60  Ibs.  per  sq.  in.,  and  produces  5  tons  of  cake  per  24  hours,  having 
a  moisture  content  of  75%.  Estimated  cost  of  operation  is  $3.46  per  ton  of 
cake.  MR.  G.  W.  FULLER  estimates  the  cost  of  pressing  activated  sludge  at 
about  $3.00  per  ton  of  dry  solids,  or  $2.70  per  ton  with  10%  moisture.  PEARSE 
and  RICHARDSON  (Ref.  No.  271)  estimate  the  cost  of  pressing  sludge  from 
stockyards  sewage  at  $5.72,  based  on  96  tons  of  dry  material  daily.  In  the 
discussion  following,  (pp.  57-62,  81-96)  reference  was  made  to  sludge  from 
the  activated  process  by  C.  E.  A.  WINSLOW,  R.  S.  WESTON,  G.  B.  KERSHAW, 
and  F.  A.  DALLYN. 

366  Water  purification  and  sanitation.     S.  RIDEAL.    Ann.  Reports  Soc.  Chem. 
Ind.  on  the  Progress  of  Appl.  Chem.  2,  461-3.    A  brief  general  review  of 

the  activated  sludge  process  is  given  for  the  year  1917.  English  plants 
referred  to  are:  Manchester,  (Withington  works)  Salford,  Worcester,  Stam- 
ford, Lincoln,  and  Sheffield.  American  plants  mentioned  are:  Milwaukee, 
Houston,  Fort  Worth,  and  Chicago. 

367  Tests  of  air  diffusers  for  the  activated  sludge  process.     E.  BARTOW  and 
F.  L.  MICKLE.     Eng.  &  Contg.  52,  41-2.     III.  State  Water  Survey  Bull 

15,  116-20..  Engineer  128,  146.  Chem.  Abst.  13,  2406.  Authors'  conclusions: 
(1)  Filtros  plates  proved  the  most  efficient  of  the  three  types  of  air  diffusers, 
as  evidenced  by  the  analytical  data.  They  gave  a  sludge  that  settled  rapidly 
leaving  clear  and  stable  effluents.  (2)  The  degree  of  porosity  of  the  filtros 
plates  made  no  apparent  difference,  for  the  coarse  and  fine  grades  of  plates 
gave  practically  the  same  results.  (3)  The  wood  block  diffusers  gave  un- 
stable effluents  in  the  majority  of  samples.  With  these  effluents  the  chemical 
results  were  not  as  satisfactory  as  with  those  from  filtros  plates.  (4)  The 
wooden  blocks  were  very  difficult  to  install,  and  even  in  the  short  time  they 
were  in  service  they  showed  evidence  of  marked  deterioration.  Until  these 
defects  can  be  remedied  their  installation  in  working-scale  plants  is  impractica- 
ble. (5)  The  perforated  pipes  gave  the  least  satisfactory  chemical  results. 
The  majority  of  the  effluents  were  unstable.  (6)  Clogging  of  the  diffusers 
during  the  period  covered  by  these  experiments  was  not  sufficient  to  have 
practical  significance. 

65 


The  Activated  Sludge  Process 

368  Experimental   study   of   the   extraction   of  grease   from   dried   activated 
sludge.     D.  F.  MCFARLAND.     III.  State   Water  Survey  Bull   15,  108-15, 

(1917).  Eng.  &  Contg.  52,  196-7.  Chem.  Abst.  13,  2406.  Using  petroleum 
ether  as  a  solvent,  4.16  to  6%  grease  was  extracted  from  dried,  untreated 
sludge  produced  in  the  experimental  activated  sludge  plant.  On  treating  with 
acid,  the  yield  of  grease  was  5.81  to  8.10%. 

1918 

369  Notes  on  the  activated  sludge  tests  at  Cleveland,  O.    R.  W.  PRATT.    Am. 
Jour.  Public  Health  8,  55-7.     Gives  results  of  recent  experiments.     A 

clear  effluent  stable  for  36  hours  may  be  produced  with  0.75  cu.  ft.  of  air  per 
gallon  in  2  hours,  using  25%  activated  sludge.  The  sewage  treated  is  high 
in  iron  and  1.75  hours  more  aeration  is  necessary  to  remove  the  iron  color.  A 
hydroturbine  compresses  the  air  which  is  diffused  through  filtros  plates.  Dry- 
ing the  sludge  on  sand  beds  required  too  large  an  area,  and  7  days  were  re- 
quired to  reduce  the  moisture  to  75%.  Centrifuging  has  given  the  best  results. 
Sludge  averaged  4%  ammonia,  half  of  which  is  in  available  form.  Estimated 
treatment  cost  is  given  for  a  500,000  gallon  plant. 

370  The  treatment  of  sewage  by  the  activated  sludge  process.     ANON.     Am. 
City  18,  1-4;  114-9;  199-203.     An  installment  article  from  a  paper  by 

MR.  T.  C.  HATTON  read  before  the  war  convention  of  the  Am.  Pub.  Health 
Assoc.,  in  which  the  following  subjects  are  considered.  Principles  of  the 
process;  character  of  the  sewage  to  be  treated;  character  of  the  effluent  re- 
quired; type  of  aerating  and  sedimentation  tanks;  extended  studies  of  sedi- 
mentation; types  of  air  diff users  and  their  ratio  to  tank  surface  area;  period  of 
aeration  and  sedimentation;  volume  of  air  required;  percentage  of  activated 
sludge  and  volume  to  handle;  removing  sludge  from  sedimentation  tanks  and 
dewatering  same;  and  special  studies  of  dehydrating  apparatus.  Illustrations 
of  the  Milwaukee  plant  accompany  the  article. 

371  Activated  sludge  and  the  treatment  of  packinghouse  wastes.     LANGDON 
PEARSE.     Am.  Jour.  Public  Health  8,  47-54.     Jour.  Am.  Leather  Chem. 

Assoc.  13,  145-55.  Jour.  Soc.  Chem.  Ind.  37,  348A.  Results  and  conclusions  of 
experiments  carried  on  at  the  Chicago  stockyards.  More  fully  covered  in 
references  326  and  327. 

372  Activated   sludge  in  the  treatment   of   sewage.     M.  YOUNG   and   S.   E. 
MELLING.    Sanitary  Record  61,  38,  68,  90,  122.    Surveyor  53,  42-4.    Jour. 

Royal  Sanit.  Inst.  39,  10-25.  Chem.  Abst.  12,  1325.  Abst.  Bact.  3,  41.  General 
principles  and  bacterial  actions  involved  are  explained.  Diffusers  for  air  dis- 
tribution are  practicable  for  economic  reasons.  Experiments  at  the  Davyhulme 
works  (Manch.,  Eng.)  show  that  a  pulsating  air  supply  is  advantageous  and 
minimizes  the  clogging  of  the  diff  users.  At  Salford  (Eng.)  about  22%  sludge 
by  volume  is  used  with  good  results,  with  a  sewage  containing  considerable 
trade  waste  which  at  times  has  a  very  inhibitory  character.  Perforated  pipes 
were  used  in  these  experiments  for  diffusing  air,  and  although  irregular  clog- 
ging of  the  air  jets  occurred,  the  sludge  remained  active  and  was  distributed 
satisfactorily  in  the  various  chambers.  Results  were  obtained  which  met  the 
dissolved  O  and  suspended  solids  limits  of  the  Royal  Commis.  Cost  of  treat- 
ment depends  largely  on  power  costs.  Claims  are  made  by  the  inventors  of 
the  pulsating  apparatus  (Ref.  No.  33)  that  a  50%  saving  in  power  can  be 
effected  by  its  use.  Aside  from  this  saving  two  desirable  effects  are  ensured: 
(1)  That  all  the  sludge  is  carried  to  the  surface  periodically,  and  (2)  that  the 
evenness  of  distribution  is  improved.  The  authors  also  point  out  the  following 
as  constituting  decided  advantages  of  the  process: — (1)  A  very  satisfactory 
effluent  is  obtainable.  (2)  Plant  can  be  built  nearer  to  cities,  avoiding  long 
outfall  sewers.  (3)  Fly  nuisance  is  avoided  as  activated  sludge  has  no 
offensive  odors.  (4)  The  recovery  of  the  N  and  its  fertilizer  value.  Precau- 
tions to  be  observed  in  order  to  obtain  satisfactory  results,  are  enumerated. 


Abstract  Bibliography — 1918 

373  Sewage  treatment  at  Manchester.  (Eng.)   Activated  sludge  research  work. 

ANON.  Surveyor  53,  4-5.  Chem.  Abst.  13,  354.  Work  has  been  carried 
on  in  50-gallon  casks  with  mixed  domestic  sewage  and  an  acid  trade  waste 
from  chemical  plants.  Experimental  runs  indicate  that  the  activated  sludge 
process  is  successful  in  the  presence  of  wastes  from  the  manufacture  of 
sulphate  of  ammonia,  products  from  benzene  and  aniline,  and  from  a  dye 
works,  but  more  time  is  required  for  aeration.  0  absorption  and  ammonia 
figures  are  given. 

374  The  activated  sludge  experiments  at  Pasadena,  Calif.     ANON.     Eng.  & 
Contg.  49,  36-7.     Chem.  Abst.  12,  842.    Covers  results  obtains  from  Jan. 

29,  to  Sept.  1,  1917,  at  the  experimental  plant.  (Ref.  No.  349.)  A  grit  cham- 
ber, diverting  box  and  rag-picker  was  installed  ahead  of  the  aerating  tank. 
The  plant  was  operated  on  both  the  fill  and  draw  and  continuous  plans,  and 
filtros  plates  set  in  individual  cast-iron  holders  diffused  the  air.  With  a  4-hour 
aeration  period  and  an  air  consumption  of  1  cu.  ft.  per  gallon  of  sewage,  "ex- 
ceedingly fine"  results  were  obtained. 

375  Definitions   of   terms   used   in   sewerage   and   sewage   disposal    practice. 

ANON.  Eng.  &  Contg.  49,  38-9.  Surveyor  53,  46-8.  Amended  report 
of  the  committee  on  sewerage  and  sewage  disposal  of  the  Am.  Pub.  Health 
Assoc.  Definition  for  activated  sludge  same  as  in  Ref.  No.  202. 

376  Bacterial  treatment  of  sewage.    ANON.    Engineering  105,  40-1.    Sci.  Am. 
Suppl.  85,  167.     Chem.  Abst.  12,  1224.     Briefly  refers  to  the  slate  beds 

hydrolytic  tanks  as  forerunners  of  the  activated  sludge  process,  and  to  the 
suggestions  of  DR.  G.  J.  FOWLER,  made  in  1914,  that  sewage  could  be  purified 
in  tanks  without  the  aid  of  filters. 

377  Fourth  Annual  Report  of  the  Milwaukee  Sewerage  Commission.     T.  C. 

HATTON  and  W.  R.  COPELAND.  Pamphlet  pp.  70.  (Jan.  15,  1918.) 
Covers  the  following  activated  sludge  investigations  made  during  the  year 
ending  1917  at  the  testing  station.  Aeration  of  sewage  in  tanks  10  and  15  ft. 
deep,  with  tabulated  results;  aeration  periods  of  2.4  to  11  hours  using  0.6  to 
2.8  cu.  ft.  of  air  per  gallon  with  tabulated  results  and  discussion  of  the  ad- 
vantages and  disadvantages  of  various  combinations  from  an  economic  point 
of  view.  Comparison  of  perforated  pipes,  wood  blocks,  and  filtros  plates  as 
air  diffusers,  with  the  merits  and  demerits  of  each  considered.  But,  "*  *  * 
all  questions  in  regard  to  air  diffusers,  size  of  bubbles,  etc.,  sink  into  insig- 
nificance when  compared  to  the  importance  of  furnishing  clean  air  *  *." 
Sludge  settlement  experiments  with  rectangular  tanks  having  flat  bottoms, 
steep  coned  bottoms,  and  flat  coned  bottoms;  and  with  Dorr  thickeners  of 
different  depths,  show  that  when  the  sludge  has  been  well  aerated  the  volume 
returned  by  the  15  ft.  deep  Dorr  thickener  was  reduced  to  20%  of  the  raw 
sewage  flow,  and  to  a  moisture  content  of  less  than  98%.  Concentration  of 
sludge  by  treatment  with  sulphuric  acid,  shows  that  settled  sludge  containing 
about  98%  of  water,  can  be  dewatered  by  the  acid  to  91%  in  2.25  hours,  but 
that  at  1  cent  per  Ib.  for  60  degree  Be.  acid,  the  cost  of  acid  alone  would  be 
about  $1.00  per  million  gallons  of  sewage,  to  which  another  dollar  should  be 
added  for  heating  the  sludge,  handling  acid,  etc.  Sludge  pressing  with  the 
Worthington  and  Simplex  plate  presses,  showed  in  both  cases  press  cakes 
carrying  72  to  83%  moisture.  A  Smith  direct  heat  dryer  reduced  a  press 
cake  of  75-80%  moisture  to  4-10%,  and  a  Buckeye  semi-direct  heat  dryer 
reduced  the  moisture  from  61-83%  to  4-18%.  Several  tables  of  analytical  and 
other  data  accompany  the  report. 

378  Sewage  tests  at  Syracuse,  N.  Y.    NEWS  ITEM.    Mimic.  Jour.  44,  59.    The 
city  is  awaiting  the  results  of  tests  now  being  made  by  Chief  Eng.  G.  D. 

HOLMES  to  determine  whether  the  activated  sludge  or  aerated  filter  systems 
is  best  suited  for  treatment  of  the  city  sewage.  At  the  testing  station,  crude 
sewage  is  pumped  to  a  grit  chamber  30  ft.  long,  and  then  passed  through  a 

67 


The  Activated  Sludge  Process 

bar  screen  with  0.75  inch  spacing.  Part  of  it  then  enters  the  activated  sludge 
tank,  the  rest  going  to  two  Dortmund  tanks,  one  with  a  horizontal  flow  filter, 
the  other  with  a  vertical  flow  aerated  gravel  filter.  (Cf.  Ref.  363.) 

379  Activated  sludge  in  the  treatment  of  sewage.    DISCUSSION.    Surveyor  53, 
117-9.     Discussion  of  YOUNG  and  MELLING'S  paper    (Ref.  No.  372)    in 

which  MR.  T.  CAINK,  by  letter,  stated  that  atmospheric  temperatures  as  low 
as  21°F.,  sewage  temperature  43°F.,  had  no  appreciable  effect  on  the  purifica- 
tion at  Worcester.  (Eng.)  He  had,  however,  observed  that  the  activated 
sludge  process  was  very  sensitive  to  sudden  increases  in  the  rate  of  flow 
through  the  aeration  tank,  the  effluent  being  inferior ;  but  if  the  same  increased 
rate  was  reached  gradually,  it  was  without  effect  on  the  degree  of  purification. 
DR.  E.  ARDERN  related  some  experiences  at  the  Withington  works,  (Manchester, 
Eng.),  where  400,000  gallons  of  sewage  was  being  treated  daily  with  satis- 
factory effluent,  and  with  about  75%  of  the  volume  of  air  originally  estimated 
on.  In  his  opinion  sludge  dewatering  and  drying  remained  one  of  the  most 
important  problems  to  solve.  MR.  P.  GAUNT,  MR.  W.  CLIFFORD,  DR.  S.  RIDEAL, 
MR.  G.  P.  MILN,  MR.  W.  D.  SCOULLER,  MR.  J.  A.  COOMBES,  and  MR.  G.  W. 
LACEY  brought  up  questions  of  sludge  disposal  and  utilization,  the  relative 
merits  of  perforated  pipes  and  porous  tiles  as  air  diffusers,  the  matter  of  costs, 
and  the  possibilities  of  converting  existing  plants  into  activated  sludge  plants. 

380  Sewerage  and  sewage  disposal.    The  activated  sludge  process.    EDITORIAL. 
Surveyor  53,  71-3.     Reviews  the  progress  of  the  process  in  England  and 

America;  suggests  standard  units  for  measuring  sewage,  air,  etc.,  so  as  to 
get  comparable  figures  on  volumes  used;  notes  that  porous  plates  have  been 
found  most  satisfactory  for  air  diffusion;  and  comments  on  the  experiments 
on  packinghouse  wastes  made  at  Fort  Worth,  Texas,  and  the  proposed  plant 
for  the  Chicago  stockyards. 

381  Activated    sludge    equipment.      NEWS    ITEM.      Surveyor   53,    106.      The 
CLIFFORD   patent   tank   equipment    (Ref.    No.    275)    for   securing   rapid 

settlement  of  activated  sludge  has  proved  a  great  success  at  the  Withington 
works  and  at  Stamford.  JONES  &  ATTWOOD  air  diffusers  have  been  in  use  over 
two  years  and  showed  no  signs  of  deterioration. 

382  Sludge  disposal.    ANON.    Surveyor  53,  114-5.     Abstract  from  the  paper 
by  K.  ALLEN  before  the  Am.  Soc.  Munic.  Impvts.     (Cf.  Ref.  365.) 

383  Activated  sludge  treatment.    W.  C.  MOOR,  Fort  Worth,  Tex.   U.  S.  Patent 
1,254,833,  Jan.  29,  1918.     (Assigned  to  ARMOUR  &  Co.,  Chicago.    Applica- 
tion filed  July  9,  1917.    6  claims.)     Off.  Gaz.  246,  1097.    Jour.  Soc.  Chem.  Ind. 
37,  193A.     Chem.  Abst.  12,  731.     Claim  5:— The  method  of  dehydrating  acti- 
vated sludge  which  consists  in  heating  the  same  to  above  30  C.,  then  subjecting 
the  same  to  the  action  of  sulphuric  acid  whereby  coagulation  takes  place  ac- 
companied by  the  generation  of  gas  therein  and  the  coagulated  sludge  is  caused 
to  float,  and  then  separating  the  coagulated  floating  sludge  from  the  liquid 
and  drying. 

384  Activated  sludge  treatment.     G.  B.  MULLOY,  Chicago,  111.     U.  S.  Patent 
1,254,836,  Jan.  29,  1918.     (Assigned  to  ARMOUR  &  Co.,  Chicago.    Applica- 
tion filed  July  9,  1917.     1  claim.)     Off.  Gaz.  246,  1097.    Jour.  Soc.  Chem.  Ind. 
37,  193 A.     Chem.  Abst.  12,  731.     The  improvement  in  the  activated   sludge 
method  of  treatment  as  applied  to  industrial  sewage,  which  consists  in  pre- 
liminary diluting  the  raw  sewage  with  effluent  from  previously  treated  sewage. 

385  Activated  sludge  treatment.     G.  L.  NOBLE,  Chicago,  111.     U.  S.  Patent 
1,254,841,  Jan.  29,  1918.     (Assigned  to  Armour  &  Co.,  Chicago.     Appli- 
cation filed  July  9, 1917.    2  claims.)     Off.  Gaz.  246,  1099.    Jour.  Soc.  Chem.  Ind. 
37,  193A.    Chem.  Abst.  12,  731.     Claim  2: — The  improvement  in  the  activated 
sludge  method  of  treatment  as  applied  to  sewage,  which  consists  in  drawing  off 

68 


Abstract  Bibliography — 1918 

the  activated  sludge  from  previously  treated  sewage,  aerating  such  sludge  for  a 
period  of  about  3  hours  after  its  withdrawal  to  enhance  the  virility  of  the 
aerobic  organisms  therein,  and  then  inoculating  the  raw  sewage  with  such 
re-vitalized  sludge. 

386  Activated  sludge  defined.    ANON.    Eng.  News-Record  80,  205.    Can.  Engr. 
34,  144.     Definition  as  given  in  Ref.  No.  202. 

387  Filtros  air  diffusing  plates  used  in  the  activated  sludge  process  of  sewage 
treatment.     ANON.     Munic.  Eng'rg.  54,  78-9.     A  general  description  of 

filtros,  noting  the  advantages  of  its  physical  properties  as  an  air  diffusion 
medium,  and  names  of  several  localities  where  it  is  in  use  in  activated  sludge 
plants. 

388  Activated  sludge  treatment.     EDITORIAL.     Surveyor  53,  125.     Refers  to 
YOUNG  and  MELLING'S  paper  (Ref.  No.  372)  and  comments  on  the  useful 

discussion  that  followed  its  presentation,  especially  that  in  regard  to  handling 
of  the  sludge. 

389  Costs  of  sewage  screens  at  Milwaukee.     T.  C.  HATTON.     Eng.  News- 
Record  80,  272.    In  a  letter  to  the  editor  MR.  HATTON  corrects  an  error 

in  his  reply  to  G.  B.  GASCOIGNE'S  letter  (Ref.  No.  356)  pertaining  to  the 
Operating  costs  of  the  screens  at  the  activated  sludge  plant  in  Milwaukee, 
which  should  be  $0.46  per  million  gallons  or  a  total  of  approximately  $14,000 
annually,  and  not  half  of  those  figures  as  erroneously  stated. 

390  Cleveland  may  use  fine  screens  for  sewage.     ANON.     Eng.  News-Record 
80,  382.    Refers  to  the  activated  sludge  process  only  as  in  Ref.  No.  357. 

391  Sewage  treatment  and  disposal.    G.  B.  KERSHAW.     Can.  Engr.  34,  243-5. 
Surveyor  53,  197.    Eng.  &  Contg.  49,  595-7.     Chem.  Abst.  12,  1491.     At 

the  conclusion  of  an  article  on  various  methods  of  sewage  purification,  the 
author  expresses  the  belief  that  the  activated  sludge  process  has  a  promising 
future,  and  that  economical  methods  of  dewatering  the  sludge  and  its  value 
as  a  fertilizer,  will  determine  the  net  cost  of  the  process. 

392  Activated  sludge  disposal  at  Houston,  Texas.     NEWS  ITEM.     Oil,  Paint 
and  Dru.g  Rep.  93,  27.    The  city  of  Houston  will  erect  an  addition  at  the 

north  side  disposal  plant  which  will  be  used  for  the  manufacture  of  fertilizer 
from  dried  activated  sludge.  Estimated  cost  $70,000. 

393  Activated  sludge  process.     EDITORIAL.     Surveyor  53,  229.     Comment  on 
a  paper  by  T.  C.  HATTON,  (Ref.  No.  333)  in  which  the  editor  notes  that 

Mr.  Hatton  confirms  the  stand  long  held  by  the  Surveyor  that  the  quality  of 
effluent  should  be  suited  to  local  needs,  and  controlled  by  varying  the  amount 
of  air  according  to  conditions  of  dilution. 

394  Purification  of  sewage  by  aeration  in  the  presence  of  activated  sludge. 

R.  G.  TYLER.  Proc.  Texas  Assoc.  Am.  Soc.  C.  E.  5,  7-13.  A  general 
description  of  the  process,  covering  preliminary  treatment,  aeration,  settle- 
ment, sludge  dewatering,  etc.,  with  reference  to  the  work  done  at  Chicago, 
Cleveland,  Fort  Worth,  Houston,  Milwaukee,  San  Marcos  and  Urbana.  Skilled 
supervision  is  important.  Power  costs  must  be  low  and  at  least  one  million 
g.  p.  d.  handled  to  be  economical  for  small  cities.  Each  proposition  must  be 
worked  out  on  its  own  merits.  An  experimental  plant  is  under  construction 
at  Austin  by  the  Univ.  of  Texas  in  conjunction  with  the  city. 

395  Sewage  terms  recommended  for  adoption  as  a  standard  by  a  committee 
of  the  Am.  Public  Health  Assoc.     ANON.     Munic.  Jour.  44,  223-5.     An 

amended  report  which  refers  to  the  activated  sludge  process  as  in  reference 
No.  202. 

69 


The  Activated  Sludge  Process 

396  Appaartus  for  purifying  sewage.    GRIFFITHS  &  HARTLEY.    British  Patent 
Application  No.  4,726,  March  18,  1918.     Jour.  Soc.  Chem.  Ind.  37,  196A. 

397  Activated  sludge  developments.    ANON.    Can.  Engr.  34,  294.    Chem.  Abst. 
12,  1674.     A  large  settling  tank  at  the  Davyhulme  works    (Manchester, 

Eng.)  is  to  be  converted  into  an  activated  sludge  tank  capable  of  treating  one 
million  gallons  of  sewage  per  day.  The  Withington  works,  designed  to  treat 
250,000  g.  p.  d.  has  had  new  features  introduced  which  has  increased  its 
capacity  to  400,000  g.  p.  d.  The  Worcester  (Eng.)  activated  sludge  plant  has 
fulfilled  the  city  engineer's  expectations  in  every  respect. 

398  Activated  sewage  sludge.     ANON.     Engineer  125,  297-8.     Considers  the 
several  methods  of  sludge  dewatering  and  drying,  with  particular  ref- 
erence to  the  tests  at  Milwaukee.     The  commercial  value  of  the  dried  sludge 
and  methods  of  marketing  same  are  also  discussed. 

399  Sewage  sludge  as  fertilizer.     ANON.     Surveyor  53,  314.     Gives  value  of 
sewage  sludges  on  the  basis  of  their  nitrogen  and  phosphoric  acid  con- 
tent, as  fixed  by  the  British  Government  order,  and  mentions  a  patent  sludge 
drier  using  waste  steam  which  can  handle  from  20  to  30  tons  of  sludge  daily, 
and  requires  but  two  men  to  operate. 

400  Considerations  leading  to  the  recommendations  for  fine  screens,  sprinkling 
filters,  humus  tanks  and  sludge  recovery,  as  the  sewage  disposal  method 

for  Indianapolis,  Ind.  ANON.  Eng.  &  Contg.  49,  368-72.  From  a  paper  by 
G.  W.  FULLER  presented  at  a  meeting  of  the  Ind.  Sanit.  and  Water  Supply 
Assoc.  on  March  28,  1918.  The  activated  sludge  process  is  incidentally  re- 
ferred to  as  in  references  Nos.  346  and  347. 

401  Small  activated  sludge  plant  proposed  at  Chicago.     NEWS  ITEM.     Eng. 
News-Record  80,  734.     Plans  for  an  intercepting  sewer  and  an  activated 

sludge  plant  are  proposed  by  the  Sanitary  District  of  Chicago  to  treat  the 
sewage  from  Melrose  Park,  Maywood,  River  Forest  and  other  villages  having 
a  total  population  of  about  30,000.  Estimated  cost  $750,000.  (Cf.  Ref.  No. 
598.) 

402  Purification  of  sewage.     W.  JONES.     Canadian  Patent  183,586,  April  16, 
1918.     Chem.  Abst.  12,  1326.    Air  is  supplied  to  the  sewage  under  treat- 
ment at  different  points  periodically,  to  stimulate  the  bacteria  in  the  sewage. 
(Cf.  Brit.  Patent  1,141,  Ref.  No.  33;  U.  S.  Pat.  1,247,541,  Ref.  No.  342.) 

403  Rockaway   Valley   sewage   plans   approved.     NEWS   ITEM.     Eng.   News- 
Record  80,  839.  Plans  for  the  diversion  of  sewage  of  Rockaway  Valley 

towns  to  a  point  below  the  Boonton  dam  of  the  Jersey  City  water  supply,  and 
treatment  of  the  sewage  there  by  the  activated  sludge  process,  were  approved 
by  the  N.  J.  State  Dept.  of  Health  on  April  9,  1918. 

404  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  and 
JONES  &  ATTWOOD,  L/TD.,  Amblecote,  Eng.    British  Patent  132,826,  April 

27,  1918.  Jour.  Soc.  Chem.  Ind.  38,  876A.  In  the  activated  sludge  process  of 
sewage  treatment,  the  aeration  tank  is  constructed  in  longitudinal  sections 
with  the  angles  between  the  walls  and  floor  rounded  off,  and  also  with  the  top 
of  the  walls  made  to  overhang,  so  as  to  partly  cover  the  top  of  the  tank,  the 
overhanging  portions  being  curved  on  their  under  surface  to  the  same  radius 
as  the  bottom  of  the  wall.  Air  diffusers  are  placed  in  the  side  walls  near  the 
bottom,  and  the  combined  action  of  the  air  and  the  rounded  portions  is  to  give 
a  circular  motion  to  the  sewage  in  a  transverse  direction  to  the  flow,  and  also 
to  cause  the  air  to  circulate  in  the  outer  layers  of  the  sewage.  The  general 
direction  of  flow  is  down  one  longitudinal  section  and  back  by  another,  and  so 
on.  The  tank  is  also  divided  into  sections  by  transverse  walls,  with  the  com- 
municating openings  between  sections  placed  near  the  source  of  air  supply. 

70 


Abstract  Bibliography — 1918 

By  this  means  all  the  sewage  is  made  to  pass  several  times  near  the  sources 
of  air  supply  in  its  passage  through  the  tank.  Various  modifications  in  the 
position  of  the  air  supply  and  in  the  wall  structure  are  described.  (Cf.  U.  S. 
Pat.  1,341,561,  Ref.  No.  561.) 

405  The  fertilizing  value  of  activated  sludge.     G.   G.   NASMITH   and   G.   P. 
McKAY.     Jour.    Ind.   Eng.    Chem.    10,    339-44.      Can.   Engr.   34,    377-82. 

Eng.  News-Record  80,  1193.  Eng.  &  Contg.  50,  31-2.  Jour.  Soc.  Chem.  Ind.  37, 
384A.  Chem.  Abst.  12,  1229.  An  extended  study  of  the  subject  including  a 
report  of  plot  experiments  with  activated  sludge.  It  appears  to  be  especially 
valuable  to  root  crops.  Compared  with  a  standard  barnyard  manure  used  by 
farmers,  the  increase  in  yields  due  to  activated  sludge  was: — with  beets,  138%; 
radishes,  40%;  late  radishes,  316%;  lettuce,  103.3%  beans,  77.3%;  tomatoes, 
291%;  onions,  3  varieties,  81.1,  191,  and  554%.  No  increase  was  obtained  with 
carrots.  The  drying  and  handling  of  the  sludge  is  also  discussed. 

406  Note  on  the  fertilizing  value  of  activated  sludge.    PAUL  RUDNICK.    Jour. 
Ind.  Eng.  Chem.  10,  400.    Chem.  Abst.  12,  1329.    In  a  letter  to  the  editor, 

the  author  claims  that  the  experimental  work  of  NASMITH  and  McKAY  (Ref. 
No.  405)  and  of  BARTOW  and  HATFIELD  (Ref.  Nos.  84  and  118)  does  not  rep- 
resent conditions  which  will  prevail  in  practice.  The  good  results  of  the 
latter  two  are  probably  due  to  the  fact  that  their  experiments  were  made  with 
sterilized  soil,  in  which  the  nitrifying  organisms  in  the  activated  sludge  will 
work  as  well  as  in  unsterile  soil,  though  this  is  not  the  case  with  dried  blood. 
In  actual  practice  sterile  soil  is  not  used. 

407  Aeration  of  sewage  and  other  impure  liquids.     O.  STOTT,  Birmingham, 
and  E.  R.  JONES,  Stourbridge,  Eng.    British  Patent  133,722,  May  14,  1918. 

Jour.  Soc.  Chem.  Ind.  38,  961A.  In  the  activated  sludge  process  of  sewage 
purification,  the  treatment  tank  is  provided  with  a  propeller  disposed  longi- 
tudinally on  the  surface  of  the  sewage.  The  propeller  blades,  which  are  of 
the  feathering  type,  introduce  air  into  the  surface  layer  of  the  liquid  and 
induce  a  surface  current  transversely  to  the  direction  of  flow.  Guides  are 
placed  in  the  tank  to  facilitate  the  continuation  of  the  current  at  the  sides 
and  across  the  bottom  of  the  tank.  The  propeller  may  be  submerged  in  the 
sewage,  in  which  case  air  is  introduced  into  the  surface  by  a  blower  or  other 
means.  (Cf.  U.  S.  Pat.  1,343,797,  Ref.  No.  566.) 

408  The  development  of  sewage  treatment.     K.  ALLEN.     Munic.  Eng'rg.  54, 
244-9.    Chem.  Abst.  13,  49.    Development  of  the  activated  sludge  process 

has  been  hindered  by  the  war,  but  valuable  data  has  been  secured  at  Milwaukee, 
Urbana,  and  Chicago.  Removal  of  the  coarser  particles  by  screens  has  reduced 
the  volume  of  air  required.  Tank  details,  types  of  diffusers,  etc.,  are  yet  to  be 
standardized.  The  advantages  of  the  activated  sludge  process  are  the  small 
space  required  and  the  recovery  of  values  from  the  sludge.  Brief  reference  is 
made  to  methods  of  sludge  handling. 

409  Purification  of  sewage  by  aeration.    Activated  sludge  tanks  at  Lawrence 
Experiment  Station.     EDITORIAL.     Surveyor  53,  457.     Extracts  from  the 

1916  Report  of  the  Mass.  Experiment  Station.     (Ref.  No.  233.) 

410  Apparatus  for  pressing  activated  sludge.     WM.  BUCKLEY,  Chicago,  III. 
U.  S.  Patent  1,271,425,  July  2,  1918.      (Application  filed  July  20,  1916. 

4  claims.)  Off.  Gaz.  252,  187.  Jour.  Soc.  Chem.  Ind.  37,  604A.  Claim  1:— In 
an  apparatus  of  the  class  described,  a  container  for  sludge  liquid,  automatic- 
ally operating  mechanism  including  means  adapted  to  receive  a  charge  thereof 
from  said  container,  and  to  close  communication  with  said  container  there- 
after, and  a  sludge  press,  said  mechanism  operating  to  force  the  received 
charge  of  sludge  liquid  into  said  press  for  the  recovery  of  the  sludge  there- 
from, the  frequency  of  said  operation  being  dependent  upon  the  rate  of  filtra- 
tion of  the  sludge  through  the  press.  (Also  Brit.  Pat.  130,146,  Ref.  No.  413.) 

71 


The  Activated  Sludge  Process 

411  Water-purifier.     (So  titled  in  patent.)     GEO.  MOORE,  Joplin,  Mo.     U.  S. 
Patent  1,271,925,  July  9,  1918.     (Assigned  to  THE  CHEMICAL  PROCESS  Co., 

N.  Y.  City.  Application  filed  Oct.  31,  1914.  10  claims.)  Off.  Gaz.  252,  360. 
Jour.  Soc.  Chem.  Ind.  37,  603A.  Chem.  Abst.  12,  1905.  Claim  3: — In  com- 
bination, a  container,  means  for  agitating  sewage  therein,  a  container  com- 
municating with  the  first  container  and  adapted  to  allow  settling  of  solids 
entering  from  the  first  container,  means  for  discharging  thickened  materials 
from  the  lower  portion  of  the  second  container,  directly  back  to  the  first  con- 
tainer; a  third  container  communicating  with  the  upper  portion  of  the  second 
container  and  adapted  to  receive  fluid  and  solids  in  suspension  therefrom,  and 
means  for  separately  treating  products  discharged  from  the  upper  and  lower 
portions  of  the  third  container.  (Cf.  following  abst.) 

412  Sewage  treatment.     GEO.   MOORE,  Joplin,  Mo:     U.   S.  Patent  1,271,926, 
July  9,  1918.     (Assigned  to  THE  CHEMICAL  PROCESS  Co.,  N.  Y.  City. 

Application  filed  Oct.  31,  1914.  14  claims.)  Off.  Gaz.  252,  360.  Jour.  Soc. 
Chem.  Ind.  37,  603A.  Chem.  Abst.  12,  1905.  Claim  5: — In  a  process  of  the 
class  described,  as  a  continuous  operation,  maintaining  agitation  of  a  mass  of 
sewage,  previously  coagulated  sewage-solids  and  foreign  solids,  (charcoal, 
coal  dust,  peat,  etc.)  continuously  supplying  thereto  original  sewage,  drawing 
off  therefrom  fluid  portions  of  the  mass,  returning  to  the  mass  solids  from  the 
drawn  off  portion,  and  filtering  the  remaining  drawn  off  portion.  (Cf.  previous 
abst.) 

413  Apparatus  for  pressing  activated  sludge.     WM.  BUCKLEY,  Chicago,  111. 
British  Patent  130,146,  July  24,  1918.     Jour.  Soc.  Chem.  Ind.  38,  694A. 

(Cf.  U.  S.  Patent  1,271,425,  Ref.  No.  410.) 

414  Sewage  disposal  at  Houston,  Texas.    NEWS  ITEM.     Munic.  Jour.  45,  84. 
At  the  Sixth  Annual  Convention  of  the  League  of  Texas  Municipalities, 

held  at  San  Antonio  on  June  19-20,  1918,  an  illustrated  address  on  sewage 
disposal  was  delivered  by  E.  E.  SANDS,  city  engineer  of  Houston,  dealing  with 
the  activated  sludge  plant  in  that  city. 

415  The  Worcester   (Eng.)   experiments  with  the  activated  sludge   process. 
ANON.    Eng.  &  Contg.  50,  122-3.    Chem.  Abst.  13,  49.    An  existing  tank 

86  by  78  by  18  ft.  deep  was  baffled  into  36  bays,  each  21  by  8  ft.,  of  which  28 
are  used  for  aerating  and  8  for  settlement.  Perforated  pipes  are  used  with 
holes  12  inches  apart,  over  which  are  placed  porous  tiles  forming  the  bottom 
of  the  valleys.  Settling  tanks  have  60  degree  bottoms  with  6  inch  air  lifts. 
Sludge  contains  96%  of  water.  Aeration  period  is  6  hours,  with  a  flow  rate 
of  one  million  gallons  per  24  hours.  20%  sludge  carried.  Settling  period  is 
one  hour  and  40  minutes.  750,000  gallons  per  24  hours  are  actually  treated. 
Analyses  are  given  of  the  screened  sewage  and  of  the  effluent. 

416  Sprinkling-filter  system  and  auxiliaries  vs.  the  activated  sludge  process. 
T.  C.  HATTON.     Munic.  County  Eng'rg.  55,  67-70.     Engineer  124,  561. 

Chem.  Abst.  12,  2643.  A  consideration  of  the  relative  advantages  of  each  sys- 
tem. On  one  acre  the  sprinkling-filter  system  should  handle  2.5  million  gal- 
lons, the  activated  sludge  process  10  to  15  million  gallons,  with  respective 
head  losses  of  12  ft.  as  against  2  to  3  ft.  Low  temperatures  do  not  materially 
effect  the  activated  sludge  process;  it  gives  a  clarified  effluent  with  freedom 
from  odor;  and  offers  a  satisfactory  method  of  sludge  disposal.  The  cost 
per  million  gallons  for  the  sprinkling-filter  system  is  estimated  much  higher 
than  for  the  activated  sludge  process. 

417  Sewage  engineering  and  sewage  disposal.    J.  E.  WILCOX.   Munic.  Eng'rg. 
&  Sanit.  Record  62,  74,  84,  124.     Can.  Engr.  35,  224-5.     Chem.  Abst.  12, 

2642.  Abstract  of  presidential  address  British  Assoc.  of  Managers  of  Sew. 
Disp.  Works.  The  most  remarkable  work  which  has  been  done  during  the  past 
year  has  been  in  connection  with  the  activated  sludge  process,  and  in  addition 

72 


Abstract  Bibliography — 1918 

to  the  installations  in  operation  at  Worcester,  Stamford  and  Salford,  a  large 
plant  has  recently  been  installed  at  the  Withington  works,  Manchester.  For 
the  past  year  or  two  most  of  the  investigation  and  research  work  has  been 
done  in  the  United  States,  the  Milwaukee  experiments  being  especially  worthy 
of  note.  The  paper  discusses  the  principal  points  arising  in  connection  with 
the  process. 

418  Means  for  supplying  air  or  gas  in  a  more  or  less  finely  divided  state., 
W.  JONES,  Stourbridge,  and  JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Eng. 

British  Patent  131,158,  Aug.  17,  1918.  Jour.  Soc.  Chem.  Ind.  38,  790A.  A 
layer  of  cement,  concrete,  or  the  like,  is  suppored  on  a  perforated  metal  or 
other  plate  extending  along  the  upper  part  of  a  trough,  channel,  or  box. 
The  top  of  the  channel  is  narrower  than  the  lower  part  so  as  to  retain  the 
porous  layer.  Air  under  pressure  admitted  to  the  channel  passes  through 
the  porous  cement  and  escapes  from  its  surface  in  a  finely  divided  state. 

419  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  and 
JONES  &  ATTWOOD,  LT'D.,  Amblecote,  Eng.    British  Patent  132,581,  Aug. 

17,  1918.  Jour.  Soc.  Chem.  Ind.  38,  843A.  In  the  activated  sludge  method 
of  purifying  sewage,  the  aerating  tank  is  discharged  during  times  of  normal 
flow  through  an  opening  near  the  bottom.  The  opening  is  made  of  a  size 
proportionate  to  the  capacity  of  the  tank,  or  it  is  provided  with  a  regulator 
or  valve,  either  method  permitting  of  a  continuous  regulated  outflow,  carrying 
the  heavier  particles  of  sludge  to  a  settling  chamber.  The  top  of  the  aerating 
tank  is  provided  with  a  weir  which  comes  into  operation  at  times  of  abnor- 
mally increased  flow  of  sewage,  and  the  overflow  from  which  joins  the  regu- 
lated flow  passing  to  the  settling  chamber. 

420  Sewage  treatment  policies  as  influenced  by  war-time  conditions.     G.  W. 

FULLER.  Munic.  County  Eng'rg.  55,  106-8.  With  respect  to  activated 
sludge,  the  inference  is  that  high  prices  and  shortage  of  farm  labor  will  mean 
that  more  attention  will  be  paid  to  fertilizers,  and  consequently  stimulate 
investigations,  not  only  as  to  activated  sludge,  but  to  sludges  from  other 
sources. 

421  Brockton  postpones   building  its   activated  sludge   plant.     NEWS   ITEM. 
Eng.  News-Record  81,  514.     The  State  Board  of  Health  having  advised 

further  sewage  experiments,  Brockton,  Mass.,  has  postponed  until  after  the 
war,  the  building  of  its  proposed  activated  sludge  plant. 

422  The  activated  sludge  process.    J.  EADE.     Surveyor  54,  131.     Description 
of  a  small  experimental  plant  at  St.  Albans,  Eng.     Aerating  tank  is 

57  ft.  3  in.  long,  with  a  width  varying  from  5  ft.  to  7  ft.  2  in.,  of  5  ft. 
depth,  and  with  a  capacity  of  7,375  gallons.  46  diffusers  having  an  effective 
area  of  32  sq.  ft.  are  located  in  a  channel  running  the  full  length  of  the 
tank.  Ratio  1  to  10.  Three  settlement  tanks  of  612,  844,  and  2,125  gallons 
capacity,  with  hopper  bottoms  and  air  lifts  are  provided,  as  is  also  a  sludge 
re-aerating  tank  of  2,194  gallons  capacity,  with  17  air  diffusers.  Air  con- 
sumption averaged  12.5  cu.  ft.  per  cu.  ft.  of  sewage,  (about  1.67  cu.  ft.  per 
U.  S.  gal.)  treating  30,000  gallons  of  sewage  per  day,  and  giving  a  good 
effluent.  Trade  wastes  from  the  breweries,  bleaching  works,  gas  works,  a 
straw  hat  factory  and  a  tallow  factory,  have  not  caused  serious  trouble  with 
the  plant. 

423  Fertilizer  experiments  at  Toronto.    NEWS  ITEM.   Surveyor  54,  139.    Fer- 
tilizer experiments  with  activated  sludge  at  the  Toronto  sewage  works 

produced  37  bushels  of  wheat  per  acre,  as  against  13  bushels  when  the 
equivalent  amount  of  N  had  been  added  to  the  land  in  the  form  of  dried  blood. 

424  Sewage  purification  by  the  activated  sludge  process.    W.  R.  COPELAND. 
Can.  Engr.  35,  302,  315-7.     Chem.  Abst.  12,  2643.     Consideration  in  de- 

73 


The  Activated  Sludge  Process 

tail  of  sewage  aeration  from  the  standpoint  of  the  volume  of  air,  period  of 
contact,  kind  of  diffusers,  and  depth  of  tanks.  Air  was  tried  in  amounts 
ranging  from  0.6  to  2.8  cu.  ft.  per  gallon  of  sewage,  and  contact  periods 
ranging  from  2.4  to  11  hours.  Filtros  plates  proved  the  best  diffusers.  Clean 
air  is  essential.  Sedimentation  is  important  to  remove  sludge.  (Cf.  Ref.  377). 

425  Manchester   (Eng.)   activated  sludge  plant.     NEWS  ITEM.    Surveyor  54, 
166.     Refers  to   a  visit  to  the   Withington   works  by  members   of  the 

Assoc.  of  Mgrs.  of  Sewage  Disposal  works  on  Oct.  5,  1918,  at  which  time 
DR.  E.  ARDERN  related  his  recent  experiences  with  the  activated  sludge 
process. 

426  Four  methods  of  sewage  treatment  studied  at  New  Haven  testing  station. 
C.  E.  A.  WINSLOW  and  F.  W.  MOHLMAN.    Munic.  Jour.  45,  280-2,  297-9, 

321-2.  Eng.  News-Record  82,  32.  Chem.  Abst.  13,  626.  Fine  screens,  Imhoff, 
and  activated  sludge,  all  with  subsequent  chlorine  disinfection,  and  Miles' 
acid  precipitation  with  sulphur  dioxide  were  tried.  The  activated  sludge 
process  was  studied  less  as  an  oxidizing  than  as  a  clarfying  process.  Trials 
were  made  with  aerating  periods  ranging  from  2.5  to  10  hours;  air  volume 
1.1  to  2  cu.  ft.  per  gallon;  sludge  volumes  (very  dilute  sjudge)  50  to  73;  and 
sedimentation  periods  of  30  to  78  minutes.  Satisfactory  results  were  not 
obtained,  partly  because  of  faulty  design  of  settling  tank,  the  small  size  of 
the  sludge  pipes,  and  the  lack  of  a  re-aerating  tank,  but  principally  because 
of  antiseptic  trade  wastes  in  the  sewage,  mainly  copper  salts  from  munition 
works. 

427  Air  diffusing  apparatus.    C.  H.  NORDELL,  Milwaukee,  Wise.    U.  S.  Patent 
1,281,816,  Oct.  15,  1918.      (Application  filed  May  12,  1917.     2  claims). 

Off.  Gaz.  255,  524.  Jour.  Soc.  Chem.  Ind.  38,  53A.  Claim  1: — A  liquid  con- 
tainer having  means  for  aerating  the  liquid  therein,  said  means  comprising 
a  member  having  a  recess  provided  with  a  concave  bottom,  a  plurality  of 
diffusing  blocks  disposed  edge  to  edge  and  positioned  to  form  an  arch,  said 
blocks  being  disposed  in  said  recess  in  the  member,  the  curvature  of  said 
arch  conforming  to  the  curvature  of  the  bottom  of  said  recess,  curved  spacing 
ribs  disposed  between  the  plurality  of  blocks  and  the  bottom  of  said  recess, 
and  means  for  admitting  air  between  the  blocks  and  the  bottom  of  the  said 
recess.  (Cf.  U.  S.  Pat.  1,208,821,  Ref.  No.  225). 

428  Apparatus  for  the   purification  of   sewage   and   analogous   liquids.     W. 
JONES,  Stourbridge,  Eng.    U.  S.  Patent  1,282,587,  Oct.  22,  1918.     (Orig- 
inal application  filed  Oct.  9,  1914;  divided,  and  this  application  filed  Nov.  7, 
1916.     8  claims).     Off.  Gaz.  255,  772.    Jour.  Soc.  Chem.  Ind.  38,  116A.     Chem. 
Abst.  13,  151.     Claim  1: — In  an  apparatus  for  purifying  sewage,  comprising 
a  tank,  means  for  introducing  air  or  oxygen  at  the  lower  part  of  the  tank, 
said  tank  being  of  a  size  above  the  air-introducing  means  to  provide  a  ma- 
terial-receiving  area   above   and   laterially   of   such  means,   and   beyond   the 
direct  influence  of  the  air  from  such  means.      (Cf.   Brit.  Pat.   19,916,  Ref. 
No.  11). 

429  Two  sludge  problems.  A.  J.  MARTIN.  Surveyor  54,  195-6.   Chem.  Abst.  13, 
354.      Sewage  treated   by  the   activated    sludge   process   requires   from 

20  to  70  times  the  amount  of  air  necessary  to  furnish  the  O  needed  to 
combine  with  the  organic  matter.  This  excess  is  required  to  perform  the 
mixing  and  because  the  air  passes  rapidly  through  the  sewage.  The  author 
proposes  the  use  of  long  horizontal  cylindrical  tanks,  the  contents  of  which 
are  maintained  in  a  state  of  rapid  rotation,  combined  with  a  slow  longitudinal 
flow.  The  rotation  may  be  produced  by  jets  of  sewage  or  air.  For  the 
removal  of  a  considerable  part  of  the  water  or  sludge,  it  is  suggested  that 
the  sludge  be  allowed  to  settle  in  tall  shafts,  where  its  own  weight  would 
consolidate  the  material  and  force  it  out  through  doors  at  the  base  of  the 
shaft.  With  activated  sludge  it  might  be  necessary  to  blow  air  through  the 
shaft  to  prevent  de-aeration. 

74 


Abstract  Bibliography — 1918 

430  All  reports  should  be  published.     EDITORIAL.   Eng.  News-Record  81,  785. 
Comment  on  the  reports  of  the  several  engineers  respecting  the  sewage 

disposal  problems  in  Cleveland,  O.,  the  activated  sludge  process  being  one  of 
the  methods  that  has  been  considered. 

431  Sewage   sedimentation  advised   for   Cleveland,   O.     ANON.    Eng.   News- 
Record  81,  806-8.     From  a  report  by  H.  P.  EDDY  in  which  the  activated 

sludge  process  and  fine  screens  are  not  recommended  as  a  solution  of  the 
westerly  district  problem,  because  of  excess  cost  over  Imhoff  tanks  with 
disinfection,  and  because  the  activated  sludge  process  as  proposed,  was  to 
operate  only  during  the  bathing  season. 

432  The  recovery  of  grease  from  city  sewage.   C.  E.  A.  WINSLOW  and  F.  W. 
MOHLMAN.     Munic.  County  Eng'rg.  55,  173-5.     Proc.  Am.  Soc.  Munic. 

Impvts.  25,  203-22.  Makes  brief  reference  to  the  activated  sludge  process  as 
one  among  a  number  of  sewage  purification  processes  tried  at  New  Haven, 
Conn. 

433  Consolidation  of  sludge  as  a  dewatering  method.  ANON.  Eng.  &  Contg.  50, 
467.    From  a  paper  by  A.  J.  MARTIN  (Ref.  No.  429)  in  which  tall  shafts 

are  suggested.  The  author  is  not  certain  that  this  method  will  apply  to  ac- 
tivated sludge. 

434  Sewage  mixes  progressively  in  its  passage  through  tanks.   H.  W.  CLARK. 
Eng.  News-Record  81,  930-1.     Surveyor  55,  143.     Chem.  Abst.  13,  1610. 

Experiments  with  actviated  sludge  and  settling  tanks  show  that  the  time 
of  passage  of  liquid  through  a  tank  is  not  equal  to  the  number  of  hours 
it  would  take  to  fill  the  tank  as  a  given  rate  of  flow.  NaCl  or  AmCl  was 
used  to  determine  the  time  of  passage.  With  a  rate  of  10.5  hours,  sewage 
appeared  at  the  outlet  of  the  tank  in  1  hour;  50%  in  7.5  hours,  while  the 
remaining  50%  lagged  for  35  hours.  The  effluent  therefore,  was  always  a 
mixture  of  applied  and  held  sewage.  Other  similar  experiments  are 
described. 

435  Purification  of  sewage  and  analogous  liquids.     W.  JONES,   Stourbridge, 
Eng.     U.  S.  Patent  1,286,017,  Nov.  26,  1918.     (Application  filed  Oct.  18, 

1915.  4  claims).  Off.  Gaz.  256,  766.  Jour.  Soc.  Chem.  Ind.  38,  116A.  Chem. 
Abst.  13>  244.  Claim  1: — The  process  of  purifying  sewage  or  the  like,  con- 
sisting in  delivering  air  into  the  sewage  to  activate  same,  permitting  such 
activated  sewage  to  settle,  drawing  off  the  liquid,  and  utilizng  the  accumu- 
lated activated  sludge  in  the  subsequent  treatment  of  raw  sewage.  Claim  4: — 
The  process  of  purifying  sewage  or  analogous  liquid,  consisting  in  delivering 
air  into  the  liquid  in  the  presence  of  bacterial  sludge,  collecting  the  air  liber- 
ated from  the  sewage  or  one  body  of  same,  and  delivering  it  into  and  passing 
it  through  sewage  or  liquid  in  another  tank  or  body. 

436  Shanghai's  sewage  disposal  and  water  supply  problems.    ANON.  Surveyor 
54,  255.    From  a  report  on  the  situation  by  DR.  G.  J.  FOWLER,  in  which 

it  is  stated  that  the  city  must  look  forward  to  the  ultimate  inoffensive  dis- 
position of  at  least  50  million  gallons  of  sewage,  and  he  suggests  that  the 
activated  sludge  process  would  serve  both  the  sanitary  and  economic  re- 
quirements. 

437  Worcester  (Mass.)  activated  sludge  experiments.   M.  GAULT.   Ann.  report 
Supt.  Sewers.     (For  year  ending  Nov.  30,  1918).     Experiments  at  the 

100,000  gallon  activated  sludge  plant  begun  in  July,  1917,  were  suspended  on 
account  of  the  war  on  Aug.  20,  1918.  Report  on  the  13  months  operation 
to  be  issued  later.  (Cf.  Ref.  487  and  540). 

438  Apparatus  for  aerating  sewage.    A.  M.  BROSIUS,  Pasadena,  Calif.     U.  S. 
Patent  1,286,520,  Dec.  3,  1918.  (Application  filed  Aug.  28,  1916.  3  claims). 

75 


The  Activated  Sludge  Process 

Off.  Gaz.  257,  83.  Jour.  Soc.  Chem.  Ind.  38,  157 A.  Chem.  Abst.  13,  355. 
Claim  1: — In  an  apparatus  for  treating  sewage,  a  foam  chamber,  means  for 
introducing  sewage  into  said  chamber,  and  paddle  means  in  said  chamber 
for  churning  said  sewage  to  form  a  foam.  Claim  2: — In  an  apparatus  for 
treating  sewage,  a  tank,  pipe  means  for  passing  air  into  the  sewage  in  said 
tank,  and  a  power  driven  mixing  means  for  finely  subdividing  said  air  to 
form  a  foam.  Claim  3: — In  an  apparatus  for  treating  sewage,  a  tank,  a 
down-flow  pipe  for  passing  a  mixture  of  sewage  and  air  to  the  bottom  of 
said  tank,  and  a  power  driven  impeller  for  breaking  up  said  mixture  of 
sewage  and  air  to  form  a  foam,  and  for  expelling  said  foam  into  said  tank. 

439  Device  for  activating  sludge.    LESTER  E.  REIN  and  JAS.  W.  Cox,  Chicago, 
111.    U.  S.  Patent  1,286,775,  Dec.  3,  1918.     (Assignors  to  PACIFIC  FLUSH 

TANK  Co.,  Chicago,  111.  Application  filed  Oct.  6,  1916.  6  claims).  Off.  Gaz. 
257,  140.  Jour.  Soc.  Chem.  Ind.  38,  157A.  Chem.  Abst.  13,  255.  Claim  6: — 
In  a  device  of  the  class  described,  a  sewage  tank  having  an  inlet  and  an 
overflow  outlet,  a  pump  having  an  inlet  member  adapted  to  extend  into  said 
tank,  a  return  pipe  connected  to  the  exhaust  of  the  pump,  an  injector  con- 
nected to  the  return  pipe  and  adapted  to  inject  air  into  the  contents  thereof, 
and  a  deflector  guide  arranged  at  the  outlet  of  the  return  pipe  and  adapted 
to  deflect  the  discharge  therefrom  into  the  body  of  the  material  in  the  tank. 

440  Activated  sludge  research  in  India.     ANON.    Appendix  9th  Ann.  Report 
Council  Indian  Inst.  Science.     (Bangalore,  India,  1918)     Jour.  Soc.  Chem. 

Ind.  38,  4R.  Research  on  activated  sludge  has  been  carried  out  since  Nov., 
1917,  at  a  small  experimental  plant  erected  outside  the  applied  chemistry  de- 
partment. Data  have  been  obtained  for  the  construction  of  the  larger  instal- 
lation at  Sakchi  and  also  valuable  information  concerning  the  character  of 
the  sludge  under  different  conditions,  with  a  view  of  its  use  as  a  fertilizer. 

441  Sewage    pollution.      DISCUSSION.     Proc.   Am.   Soc.   Munic.   Impvts.    25, 
176-93.     Mr.   G.   B.   KERSHAW    (by  letter)    comments   on  the  activated 

sludge  process,  stating  that  he  would  like  to  see  an  activated  sludge  plant 
run  side  by  side  with  say,  a  percolating  filter  installation,  both  designed  with 
the  latest  improvements  and  treating  the  same  sewage. 

442  Water  purification  and  sanitation.    E.  ARDERN.     Ann.  Reports  Soc.  Chem. 
Ind.  on  progress  Appl.  Chem.  3,  421-7.     An  interesting  review  of  the 

activated  sludge  process  for  the  year  1918.  English  plants  mentioned  are 
those  at  Manchester,  Worcester  and  St.  Albans.  American  plants  referred  to 
are  at  Milwaukee  and  Houston. 

443  Report  of  the  provincial  sanitary  engineer.    F.  A.  DALLYN.   Ann.  Report 
Provincial  Board  of  Health  of  Ontario.    37,  58-65.    Chem.  Abst.  14,  1722. 

Work  was  undertaken  with  satisfactory  results,  to  determine  the  fertilizer 
value  of  activated  sludge. 

444  Activated  sludge  as  a  fertilizer.    W.  D.  HATFIELD  and  E.  BARTOW.   Proc. 
Am.  Soc.  Munic.  Impvts.  25,  225-57.     Covers  historical  development  of 

sewage  sludges  as  fertilizers;  theoretical  discussion  of  organic  nitrogenous 
material  and  its  decomposition  products  as  fertilizers;  expermental  results 
with  wheat,  lettuce,  radishes,  corn,  beets,  onions  and  tomatoes,  the  chemical 
constitution  of  the  organic  nitrogenous  compounds  in  activated  sludge,  which 
laboratory  tests  have  shown  to  be  principally  in  the  form  of  nucleoprotein 
and  its  decomposition  products;  and  a  statement  to  the  effect  that  garden 
experiments  in  1917  proved  that  both  wet  and  dry  activated  sludge  were 
valuable  as  fertilizers,  the  wet  sludge  giving  the  better  results.  Some  data 
on  dewatering  activated  sludge  by  coagulation  and  by  centrifugals,  are  also 
given.  (Cf.  Ref.  Nos.  84  and  118). 

76 


Abstract  Bibliography — 1919 

445  Notes  on  main  drainage  and  its  relation  to  river  and  harbor  front  im- 
provements.   MORRIS  KNOWLES  and  JOHN  M.  RICE.  Proc.  Am.  Soc.  Munic. 

Impvts.  25,  138-70.  In  the  chapter  on  "Methods  of  sewage  treatment,"  a 
brief  general  review  of  the  activated  sludge  process  is  given. 

446  Investigations  upon  the  purification  of  sewage  and  water  at  the  Law- 
rence experiment  station  during  the  year  1918.    H.  W.  CLARK.    4th.  Ann. 

Report  Mass.  State  Dept.  Health.  117-49.  A  continuous  flow  activated  sludge 
tank  was  put  into  operation  early  in  the  year,  the  average  aeration  period 
being  5.38  hours,  the  air  supply  ranging  from  1.78  to  2.80  cu.  ft.  per  gallon 
of  sewage,  diffusion  being  through  hollow  perforated  brass  discs.  Approxi- 
mately 20%  of  sludge  was  carried,  the  surplus  being  removed  at  intervals. 
The  latter  amounted  to  the  equivalent  of  770  Ibs.  of  dry  sludge  per  million 
gallons  of  sewage  treated,  and  averaged  6.15%  N,  5%  fats.  Investigations 
to  learn  the  best  volume  of  air  for  efficient  aeration,  and  studies  in  regard 
to  the  effect  of  varying  volumes  of  sludge  are  also  noted.  Several  tables  of 
analytical  data  are  included. 

447  Report  of  the  Bureau  of  Sanitary  Engineering.     V.  M.  EHLERS.     Ann. 
Report  Texas  State  Board  of  Health,     pp.  34.     (1918)      Refers  to  the 

activated  sludge  process  as  being  received  with  a  great  deal  of  favor  through- 
out the  entire  state,  8  cities  using  it  in  the  treatment  of  domestic  sewage,  and 
2  experimental  plants  treating  packinghouse  wastes.  The  first  cost  of  acti- 
vated sludge  plants  is  less  than  that  of  any  other  type  giving  the  same 
results,  but  several  features  must  be  first  considered  before  adopting  the 
process. 

448  Report  on  the  sewage  disposal  problem  of  New  Haven,  Conn.     C.  E.  A. 

WINSLOW  and  F.  W.  MOHLMAN.  Pamphlet  pp.  97.  (1918)  The  acti- 
vated sludge  plant  is  described  and  the  results  obtained  from  it  given.  (Cf. 
Ref.  Nos.  329,  338,  354,  426  and  432). 

1919 

449  Sewage  disposal  at  Manchester  (Eng.)     ANON.    Surveyor  55,  17-8.    Can. 
Engr.  36,  222-3.     Chem.  Abst.  13,  1889.     From  the  annual  report,  Man- 
chester Rivers  Dept.,  for  the  year  ending  March,  1918,  the  following  data  on 
the  activated  sludge  investigations  are  summarized.    Withington  works :  aerat- 
ing tank  100  by  20  by  6  ft.  deep,  of  55,000  gallons  capacity,  is  divided  into 
5  channels  with  bottom  on  the  ridge  and  furrow  plan,  air  diffusers  in  the 
furrows.     Area  of  net  diffusion  area  to  tank  area  is  1  to  10.     Settlement  tank 
23.5  by  26.5  by  23.5  ft.  deep  to  bottom  of  hopper,  27,000  gallons  capacity,  and 
equipped  with  CLIFFORD'S  patent  arrangement.     (Ref.  No.  274).     Sludge  is 
discharged  from  apex  of  the  tank  to  a  re-aerating  tank,  from  which  it  may  be 
returned  to  the  aerating  tank  by  air  lifts.     Plant  designed  to  treat  250,000 
gallons  daily,  with  an  average  aerating  period  of  4  hours,  and  began  opera- 
tions in  Sept.,  1917.     Detritus  chamber  and  screens  preceed  the  aeration  tank. 
Volume  of  sludge  carried  varied  from  15  to  25%.     Tabular  analytical  data 
showing  results  of  daily  treatment  of  250,000  gallons  with  a  4  hour  aeration 
period  and  1.8  cu.  ft.  of  air;  375,000  gallons  with  a  3  hour  aeration  period 
and  1.2  cu.  ft.  of  air;  500,000  gallons  with  a  2  hour  aeration  period  and  0.9 
cu.  ft.  of  air  are  given.     If  nitrification  is  not  essential,  satisfactory  effluents 
can  be  obtained  when  working  at  double  the  capacity  the  plant  was  designed 
for.     375,000  gallons  can  be  handled  easily.     Bacterial  removal  was  98-99%, 
and  the  effluents  were  highly  clarified.     Sludge,  on  a  dry  basis,  amounts  to 
somewhat  more  than  0.5  ton  per  million  gallons  of  sewage,  and  showed  on 
analysis: — Loss  on  ignition,  75.2%,  mineral  matter,  24.8%.     Nitrogen,  6.4%; 
phosphorus  pentoxide,  3.8%.    As  removed  from  the  settlement  tank  it  contains 
98.5%  water.    Davyhulme:  aerating  tank  25  by  16  by  9  ft.  deep,  operated  from 
July,  1917,  to  March,  1918,  on  the  fill  and  draw  plan,  averaging  0.5  hour  to 
fill,  5.25  hours  aeration,  1  hour,  50  min.  settlement,  and  0.5  hour  discharging. 

77 


The  Activated  Sludge  Process 

45,000  gallons  were  treated  daily  with  an  air  consumption  of  1  to  1.5  cu.  ft. 
per  gallon.  The  contemplated  million  gallon  continuous  flow  plant  is  re- 
ferred to. 

450  Purification  of  sewage.     HARTLEY  &  HARTLEY.     British  Patent  Applica- 
tion 1,604,  Jan.  22,  1919.    Jour.  Soc.  Chem.  Ind.  38,  96 A. 

451  Sewerage  and  sewage  disposal.    The  activated  sludge  process.    EDITORIAL. 
Surveyor  55,   66-9.     The  possibility  of  draining  the   sludge   on   coarse 

filters  protected  from  rain  is  discussed,  the  fertilizer  value  of  it  as  disclosed 
in  the  paper  of  NASMITH  &  McKAY  is  commented  upon,  as  is  the  paper  by 
MR.  T.  C.  HATTON  presented  before  the  Am.  Pub.  Health  Assoc.  (Ref.  No. 
370). 

452  English  activated  sludge  plants.    TRADE  NOTE.   Surveyor  55,  105.   JONES 
&   ATTWOOD  refer  to  the  plants  of  their  construction   at  Manchester, 

(Davyhulme  works)  one  million  gallons  per  day;  at  Tunstall,  250,000  gallons 
per  day;  at  St.  Albans,  at  the  Am.  Red  Cross  Hospital  near  Sarisbury  Court; 
at  a  Royal  Airship  Station  near  Worcester;  and  to  the  plants  at  Harpenden 
and  Worcester. 

453  Fifth   annual   report   of  the   Milwaukee    Sewerage    Commission.     T.    C. 

HATTON  and  W.  R.  COPELAND.  Pamphlet  pp.  51.  (Jan.  31,  1919).  The 
reports  of  Ch.  Eng.  Hatton  and  Ch.  Chem.  Copeland  for  the  year  ending 
Dec.  31,  1918,  gives  detailed  results  of  the  operation  of  the  chain  belt  fine 
screen  at  head  losses  of  from  2  to  6.7  in.,  collecting  441  to  953  Ibs.  of  screen- 
ings of  88.1  to  89.0%  moisture.  Analysis  of  these  screenings  show  an  average 
of  5.94%  N  on  a  dry  basis.  Two  aerating  tanks  15  ft.  deep  with  filtros  plates 
in  the  ratios  of  1  to  4.4  and  1  to  6.0,  treat  the  equivalent  of  16  million  gallons 
of  sewage  per  acre  per  day,  and  two  tanks  of  10  ft.  depth  with  the  filtros 
plates  in  the  same  ratios,  treat  the  equivalent  of  10  million  gallons  per  acre 
per  day.  All  4  tanks  have  a  liquid  area  of  284  sq.  ft.  All  tests  showed 
better  than  99%  removal  of  suspended  matter,  95%  bacterial  removal,  and 
effluent  stability  of  95  to  120  hours.  The  standard  aimed  at  for  these  factors 
are  95%,  90%  and  72  hours.  The  importance  of  supplying  clean  air  to  the 
diffusers  is  emphasized.  The  lines  should  be  of  non-corrosive  material  so  as 
to  prevent  scales  of  iron  rust  from  clogging  the  diffusers.  Dorr  thickeners 
in  the  sludge  settling  tanks  gave  good  service,  the  discharged  sludge  ranging 
from  97  to  99.5%  moisture,  with  the  overflow  effluent  carrying  less  than  5 
p.  p.  m.  of  suspended  solids  on  the  average.  Several  tables  of  analytical 
data  accompany  the  report. 

454  Improved  fertilizer.       G.  J.  FOWLER  and  G.  MUMFORD.       U.  S.  Patent 
1,294,080,  Feb.  11,  1919.      (Application  filed  June  1,  1916.     7  claims). 

Off.  Gaz.  259,  289.  Chem.  Abst.  13,  1121.  Claim  6:— The  herein  described 
improved  fertilizer,  consisting  of  bacterially  active  dry  sewage  sludge  of 
granular  character.  (Cf.  Brit.  Pat.  8,397,  Ref.  No.  51;  Dan.  Pat.  22,389, 
Ref.  No.  309;  Can.  Pat.  189,921,  Ref.  No.  467). 

455  Improvements  in  or  relating  to  apparatus  for  use  in  the  treatment  of 
sewage  and  other  effluents.     L.  WHYTE,  Wilmslow,  and  H.  FOTHERGILL, 

Cheadle  Hulme,  Eng.  British  Patent  104,189,  February  28,  1919.  Jour.  Soc. 
Chem.  Ind.  39,  347A.  The  object  of  the  invention  is  to  provide  means  for 
thoroughly  mixing  together  the  sewage  and  activated  sludge,  and  assuring 
that  the  whole  of  the  mixture  shall  be  brought  into  contact  with  the  atmosphere. 
Stationary  mixing  devices  in  the  form  of  an  archimedean  screw  or  spiral  are 
disposed  at  selected  points  in  the  channels,  each  being  of  appropriate  axial 
length  and  with  the  screw-like  vanes  shaped  to  fit  closely  to  the  bottom  and 
side  walls  of  the  channels,  which  may  be  of  rectangular  or  circular  form,  so 
that  the  whole  of  the  mixture  is  effected,  there  being  no  clear  flow  through  the 
channels.  The  mixing  devices  may  be  made  of  metal,  earthenware,  or  other 

78 


Abstract  Bibliography — 1919 

material.  As  the  mixture  of  sewage  and  sludge  flows  through  the  channels  a 
rotary  motion  is  imparted  to  it  and  fresh  surfaces  brought  into  contact  with 
the  atmosphere.  Adapted  to  be  used  in  either  continuous  flow  or  intermittant 
treatment  tanks. 

456  Analyses  of  sewage  and   sewage  sludges.     ANON.      Water  and  Water 
Eng'rg.     (Mar.  20,  1919).  Eng.  &  Contg.  51,  465.    Chem.  Abst.  13,  1733. 

A  typical  sewage  and  8  sludge  analyses  are  given.  Activated  sludge  shows  the 
most  N,  7.5%  on  dry  weight. 

457  Texas  activated  sludge  plants.     ANON.     Munic.  Jour.  46,  225.     From  a 
report  of  the  bureau  of  sanitary  engineering,  Texas  State  Board  of  Health, 

in  which  the  statement  is  made  that  "Texas  is  pecularly  the  home  of  the  acti- 
vated sludge  process,  there  being  10  such  plants  in  operation  there,  one  of 
them  being  the  first  city  in  the  world  to  treat  the  entire  sewage  of  a  city." 

458  City  of  Sheffield  sewage  disposal  department.    J.  HAWORTH.     Report  of 
Highway  and  Sewerage  Com.     (For  2  years  ending  March,  1919),  pp.  10. 

Sanit.  Record  63,  228-9.  Chem.  Abst.  13,  1609.  Expt.  Sta.  Record  42,  188. 
Activated  sludge  experiments  have  been  continued  and  developed,  and  two  new 
tanks  added  treating  50,000  and  60,000  gallons  of  trade  sewage  per  day.  These 
tanks  are  30  by  14  by  4  ft.  deep,  with  level  floors,  and  divided  into  channels 
about  3.25  ft.  wide.  Mechanical  agitation  is  furnished  by  2  vertical  pistons 
of  the  Root's  blower  type  which  also  circulate  the  sewage  with  a  velocity  of 
1.5  to  2  ft.  per  second  which  is  sufficient  to  prevent  sludge  settlement.  10  days 
were  required  to  produce  a  well  activated  sludge,  the  tanks  then  being  worked 
on  the  fill  and  draw  plan,  3  fillings  per  day,  continuously  and  satisfactorily  for 
the  past  3  months,  the  only  air  the  sewage  received  being  by  contact  at  the 
surface.  20  HP.  per  million  gallons  is  required.  (In  a  private  communication 
to  the  compiler,  Mr.  Haworth  states  that  a  plant  capable  of  treating  not  less 
than  one  million  gallons  is  being  constructed,  the  operation  of  which  is  expected 
in  Sept.,  1920.) 

459  Results  of  experiments  with  Miles   acid  process   of  sewage   treatment. 

E.  S.  DORR  and  R.  S.  WESTON.  Jour.  Boston  Soc.  C.  E.  6,  (April,  1919). 
Can.  Engr.  36,  455-60.  Eng.  &  Contg.  51,  510-3.  Surveyor  55,  419-21.  The 
activated  sludge  process  is  mentioned  only  by  way  of  comparison.  Sludge 
from  the  acid  process  amounts  to  only  one-seventh  as  much  as  from  the  acti- 
vated sludge  process  and  contains  less  moisture;  90%  as  against  98.5%.  (Abst. 
of  a  paper  on  this  subject  by  WINSLOW  and  MOHLMAN  in  Eng.  News-Record 
81,  1034-6,  Am.  City  20,  467-9.  (Cf.  Ref.  No.  426.) 

460  Operating  experiences  with  activated  sludge  process  for  factory  wastes. 

G.  W.  FULLER.  Can.  Eng.  38,  367-8.  Munic.  County  Eng'rg.  57,  123-5. 
Chem.  Abst.  13,  3263.  Describes  experiments  on  the  wastes  of  a  plant  handling 
cocoanut  oil,  making  edible  oil,  margarine,  etc.  150,000  gallons  per  24  hours 
with  a  temperature  of  40  C.  are  treated  by  a  plant  comprising  preliminary 
grease  trap,  aerating  tanks,  re-aerating  tank,  and  final  settling  tank.  Milk  of 
lime  may  be  added  at  the  inlet  to  aerating  chamber.  Perforated  pipes  are  used 
for  air  distribution.  Tests  showed  need  for  organic  matter,  hence  cow  manure 
is  added  at  the  rate  of  8  cu.  ft.  per  24  hours  for  the  150,000  gallons  of  waste. 
Air  is  supplied  at  the  rate  of  1.5  cu.  ft.  per  gallon;  3  hour  period  of  contact. 
3  grains  of  lime  per  gallon  are  added  at  inlet  of  final  sedimentation  tank,  pro- 
ducing a  clear  and  stable  effluent. 

461  Reading  (Eng.)  and  the  activated  sludge  process.    NEWS  ITEM.    Surveyor 
55,  282.    The  town  clerk  of  Reading  has  been  instructed  to  ascertain  the 

names  of  places  in  which  activated  sludge  installations  are  in  operation,  either 
experimental  or  otherwise,  and  whether  the  process  has  proved  successful. 

79 


The  Activated  Sludge  Process 

462  Chlorination  of  sewage.    ANON.    Munic.  Jour.  Pub.  Works  46,  266.    Can. 
Engr.  36,  404.    Chem.  Abst.  13,  1733.    At  New  Haven,  Conn.,  the  follow- 
ing p.  p.  m.  of  chlorine  were  required: — Crude  sewage  7  to  8;  activated  sludge 
effluent,  3;  Imhoff  effluent,  6;  screened  sewage,  5.     With  the  activated  sludge 
effluent,  2  p.  p.  m.  of  chlorine  reduced  the  total  bacteria  78%.    In  the  samples 
containing-  3  p.  p.  m.  of  chlorine,  the  activated  sludge  process  had  already 
reduced  the  number  of  B.  Coli  73%,  and  no  further  reduction  was  effected  by 
chlorine. 

463  Activated  sludge  process  at  Worcester  (Eng.).     NEWS  ITEM.     Surveyor 
55,  298.     Relates  to   financing  the   completion  of  the   activated   sludge 

plant.  Large  economies  in  the  working  of  the  system  should  be  assured  be- 
fore going  further. 

464  Milwaukee  sewage  pumping  station.     T.  C.  HATTON.     Fire  and  Water 
Eng'rg.  65,  (April  23,  1919).     A  description  of  the  pumping  equipment 

for  the  new  activated  sludge  plant. 

465  Report  on  the  activities  of  the  Bureau  of  Sanitary  Engineering  of  the 
Texas  State  Board  of  Health.     R.  G.  UPTON.     Proc.  Texas  Assoc.  Am. 

Soc.  C.  E.  6,  57-8.  1919.)  Over  168  sewage  systems  are  in  operation  in  Texas 
towns  and  all  have  disposal  plants  except  a  few  on  tide  water  and  elsewhere. 
The  10  or  12  activated  sludge  plants  are  producing  excellent  effluents  and  the 
process  is  referred  to  as  the  only  odorless  sewage  disposal  method  known. 

466  Apparatus  for  aerating  sewage  and  other  foul  liquids.    R.  AMES,  Brigh- 
ton, Eng.     British  Patent  143,369,  April  28,  1919.    Jour.  Soc.  Chem.  Ind. 

39,  52 5 A.  In  aerating  tanks,  a  movable  device  for  raising  the  sludge  to  the 
surface,  comprising  a  series  of  vertical  pipes  fixed  in  a  carriage,  the  lower  ends 
of  the  pipes  being  bell-mouthed,  and  the  upper  ends  being  provided  with  mush- 
room-shaped flanges.  By  means  of  an  internal  concentric  pipe,  and  an  air 
lift  consisting  of  a  conical  box  with  apex  below  and  slotted  to  allow  air  to 
escape  upwards,  or  other  suitable  device,  the  sludge  is  raised  to  the  surface 
through  the  bell-mouthed  pipes,  and  then  flows  in  a  cascade  over  the 
mushroom  flanges  back  into  the  tank,  becoming  aerated  in  the  process. 

467  Fertilizer.     G.  J.   FOWLER.     Canadian  Patent  189,921,  April  29,  1919. 
Chem.   Abst.    13,   1121.      Consisting    of   bacterially   active   non-colloidal 

sewage  sludge  rich  in  nitrogen,  in  a  state  available  for  plant  food,  made  by 
forcing  air  through  sewage  in  the  presence  of  bacteria,  thus  forming  an 
active  sludge  which  is  heated  to  sterilize  and  dry  it.  It  is  then  inoculated 
with  a  portion  of  fresh  active  sludge.  (Cf.  Brit.  Pat.  8,397,  Ref.  No.  51; 
Dan.  Pat.  22,389,  Ref.  No.  309;  U.  S.  Pat.  1,294,080,  Ref.  No.  454.) 

468  Mechanical  agitation  for  activated  sludge.    EDITORIAL.    Munic.  Jour.  Pub. 
Works  46,  349.     The  experiments  at  Sheffield,  Eng.,   (Ref.  No.  458)   ap- 
parently demonstrate  that  not  even  for  oxidation  purposes  was  applied  air 
necessary,  as  sufficient  0  is  absorbed  at  the  surface  if  the  sewage  is  kept 
agitated.     Considered  by  the  editor  a  very  promising  discovery. 

469  Activated  sludge  without  compressed   air.     ANON.     Munic.  Jour.  Pub. 
Works  46,  356.    Chem.  Abst.  13,  2248.    Descriptive  of  the  experiments  at 

Sheffield,  Eng.,  with  mechanical  agitators  which  indicate  the  possible  substi- 
tution of  them  for  compressed  air,  surface  absorption  of  the  O  being  depended 
upon  for  oxidizing  purposes.  (Cf.  Ref.  No.  458.) 

470  Activated   sewage   process   extension.     NEWS   ITEM.     Surveyor  55,   470. 
The  Worcester  (Eng.)  City  Council  has  resolved  to  carry  out  the  scheme 

proposed  by  MR.  T.  CAINK,  city  engineer,  for  applying  the  activated  sludge 
process  to  the  whole  of  the  remainder  of  the  city's  sewage  not  already  so 
treated.  The  scheme  proposes  to  treat  1.5  million  gallons  of  dry  weather  flow 
daily  at  an  estimated  cost  of  5,550  pounds. 

80 


Abstract  Bibliography — 1919 

471  Toronto   will    investigate   the    activated    sludge    process.      NEWS    ITEM. 
Can.  Engr.    37,  46.    "Officials  of  the  City  of  Toronto  will  visit  Milwaukee 

at  an  early  date  to  investigate  the  activated  sludge  process.  If  satisfied  with 
the  progress  made  at  Milwaukee  the  Toronto  City  Council  will  allow  $50,000 
for  an  experimental  unit;  which  if  successful  will  result  in  the  construction  of 
a  large  plant  to  handle  all  of  Toronto's  sewage." 

472  Reading  (Eng.)  and  the  activated  sludge  process.     ANON.     Surveyor  56, 
49.    It  is  recommended  that  the  sedimentation  tanks  be  reconstructed  for 

use  in  the  activated  sludge  process,  which  because  of  local  conditions,  can  be 
adopted  to  advantage  as  it  will  create  no  nuisance  and  produce  an  effluent  that 
would  meet  all  requirements. 

473  Separation  of  sludge  and  scum  from  sewage  and  other  liquids.     S.  H. 

ADAMS.  British  Patent  145,291,  Aug.  1,  1919.  Jour.  Soc.  Chem.  Ind.  39, 
581A.  A  sedimentation  tank  is  provided  with  an  apron  roof,  sloping  longi- 
tudinally from  near  one  wall  to  near  the  bottom  of  the  opposite  wall,  and 
suspended  on  pivots.  The  floor  of  the  tank  slopes  in  the  opposite  direction  to 
the  roof,  and  at  its  lower  side  terminates  in  a  sludge  channel.  Sewage  enters 
at  one  end  of  the  tank  and  flows  over  the  roof  towards  the  exit  pipe  at  the 
opposite  end.  Solids  settling  out  of  the  sewage  slide  down  the  roof  into  the 
lower  portion  of  the  tank  to  the  sludge  channel.  Scum  rising  from  the  floor 
of  the  tank  is  directed  by  the  under  side  of  the  roof  into  a  scum  space  at  the 
surface  between  the  top  of  the  roof  and  the  side  wall  of  the  tank,  from  which 
it  is  removed  over  a  weir  into  a  scum  channel.  When  used  for  activated  sludge 
the  tank  is  made  preferably  of  circular  form,  the  air  inlets  being  so  placed 
as  to  impart  a  revolving  motion  to  the  liquid.  In  this  case  the  exit  pipe  is 
placed  axially  and  receives  the  liquid  through  perforations  along  its  length. 

474  Problems  of  sewage  disposal   at   Shanghai,    (China).      C.    H.    GODFREY. 
Munic.  Gaz.  (Shanghai)  12,  291-6.    Surveyor  56,  225-6.     Water  &  Water 
Engr.  21,  318-20.     Chem.  Abst.  14,  583.     Extracts  from  a  preliminary 

report  covering  the  author's  observations  after  visiting  several  activated  sludge 
plants  in  the  United  States.  An  experimental  activated  sludge  plant  is  rec- 
ommended for  Shanghai. 

475  Salford  (Eng.)  and  the  activated  sludge  process.    NEWS  ITEM.    Surveyor 
56,  146.     The  Salford  Town  Council  Rivers  Committee  recommend  the 

adoption  of  the  activated  sludge  process,  successful  experiments  having  been 
carried  out  for  some  time. 

476  Activated  sludge  plant  for  Chicago  stockyards.     NEWS  ITEM.     Eng.  & 
Contg.  52,  310.     "The  committee  of  the  trustees  of  the  Sanitary  Dist.  of 

Chicago  voted  Sept.  3,  1919,  to  construct  an  activated  sludge  plant  for  the 
treatment  of  the  trade  wastes  from  the  stockyards.  It  also  voted  to  request 
the  packers  to  pay  two-thirds  of  the  cost  of  installation  and  operation." 

477  A  sewage-treatment  experiment.     ANON.     Munic.  Jour.  Pub.  Works  47, 
199-200.      Chem.  Abst.    13,   3263.     Describes   an   experimental  plant  of 

50,000  gallons  capacity  at  Mt.  Vernon,  N.  Y.,  comprising  a  rotary  driven  screen, 
24  mesh,  with  flow  from  the  outside  in,  a  special  tank  containing  both  aeration 
and  sedimentation  compartments,  and  Dorr  thickeners,  which  treat  the  sewage 
with  about  one-third  the  usual  amount  of  air.  The  plant  was  designed  and  is 
operated  by  the  Dorr  Co.,  the  object  being  to  develop  a  more  efficient  applica- 
tion of  the  activated  sludge  process.  (Cf.  Ref.  Nos.  579  and  581.) 

478  Activated  sludge  sewage  treating  plant  to  require  much  power.     ANON. 

Elect.  Review  75,  529-30.  At  the  Chicago  meeting  of  the  West.  Soc.  Eng., 
MR.  LANGDON  PEARSE  stated  that  electric  power  was  proposed  for  the  stock- 
yards' new  activated  sludge  plant,  involving  a  connected  load  of  about  12,000 
H.P.,  and  using  approximately  38,500,000  kw-hr.  annually.  Assuming  a 
power  rate  of  0.7  cent  per  kw-hr.  the  power  cost  for  a  year  would  be  about 
$270,000. 

81 


The  Activated  Sludge  Process 

479  The  utilization  of  sewage  sludge.     J.   D.   WATSON.     Munic.  Jour.  Pub. 
Works  47,  210-3;  226-7.     Can.  Engr.  37,  420-2;  427-9.     Deals  principally 

with  other  than  activated  sludge,  referring  to  it  only  in  a  quotation  from  the 
report  of  a  joint  English  Committee  as  follows: — "We  have  not  specifically 
inquired  into  the  results  to  be  obtained  from  sewage  treated  by  the  activated 
process,  but  as  a  result  of  visits  made  by  the  Committee  to  the  Manchester 
and  Sheffield  sewage  disposal  works  where  the  activation  by  aeration  and 
activation  by  agitation  processes  respectively  are  under  investigation,  it 
would  appear  that  the  residual  sludge  from  such  processes  contained  a  higher 
percentage  of  nitrogen,  and  consequently  as  a  fertilizer  would  be  of  greater 
value  than  sludge  produced  in  the  ordinary  way.  Experiments  have  been 
commenced  to  ascertain  its  fertilizing  value,  but  further  investigation  is 
necessary  to  find  out  the  best  method  of  dewatering  and  drying." 

480  Utilization  of  sewage  sludge.     EDITORIAL.    Munic.  Jour.  Pub.  Works  47, 
219.     Refers  to  sewage  sludges  in  general,  but  concludes  with  the  hope 

that  the  activated  sludge  process  now  operating  in  so  many  places,  will  furnish 
valuable  information  on  the  subject  of  their  use. 

481  Bingley  municipal  works.    Activated  sludge  experiments.    H.  BOTTOMLEY. 
Surveyor  56,   258.     Experiments   have  been   carried   out  for   about   15 

months,  successfully  treating  300,000  gallons  of  sewage  on  the  fill  and  draw 
plan,  in  a  tank  8  ft.  diam.  by  4  ft.  deep,  of  1000  gallons  capacity.  14  porous 
tiles  were  used  as  air  diff users.  After  the  7th  filling  satisfactory  results  were 
obtained  with  4  hours  aeration.  Two  fillings  per  day  treating  750  gallons  at 
each  fill  was  the  procedure  for  about  3  months.  After  some  alterations  to 
plant,  experiments  were  resumed  and  continued  for  about  12  months  with 
successful  results.  Aeration  period  varied  from  2  to  9  hours.  In  the  discus- 
sion, MR.  J.  P.  WAKEFORD  referred  to  the  mechanical  agitation  experiments 
at  the  Tinsley  works,  Sheffield,  where  two  tanks  were  being  equipped  to  handle 
200,000  gallons  daily,  agitation  being  produced  by  two  small  propellers  work- 
ing horizontally. 

482  Agreement    reached    for    packingtown   sewage   disposal.     ANON.      Eng. 
World  (Nov.  1,  1919).     Exerpt  from  a  paper  by  LANGDON  PEARSE  pre- 
sented at  the  Chicago  meeting  West.  Eng.  Soc.  in  Sept.     Material  covered  by 
Ref.  No.  533. 

483  Purification  of  sewage.     HARTLEY  &  HARTLEY.     British  Patent  Applica- 
tion No.  27,205,  Nov.  5,  1919.    Jour.  Soc.  Chem.  Ind.  38,  884 A. 

484  Economic  values  in  sewage  sludge.    R.  WELLS.    Munic.  Jour.  Pub.  Works 
47,  278-80.     Eng.  News-Record  83,  948-52.     Can.  Engr.  37,  563-6.    Proc. 

Am.  Soc.  Munic.  Impvts.  26,  55-97.  The  following  data  and  remarks  pertaining 
to  activated  sludge  are  noted  in  this  paper.  Chicago  Sanit.  Dist.  fresh  activated 
sludge  contained  5.10%  ammonia;  14.70%  grease.  When  9  months  old  it 
contained  4.40%  ammonia  and  5.0%  grease.  Syracuse,  N.  Y.,  fresh  activated 
sludge  contained  5.06%  ammonia,  and  17.7%  grease.  In  the  discussion,  MR. 
H.  T.  CALVERT  and  DR.  H.  MACLEAN  WILSON,  of  Wakefield,  Eng.,  write  that 
activated  sludge  apparently  contains  less  grease  than  fresh  sludge,  but  the 
larger  amount  of  N  increases  its  value  as  a  fertilizer.  DR.  F.  Wi  MOHLMAN 
writes  that  grease  extraction  from  activated  sludge  is  unprofitable  as  the 
amount  is  greatly  reduced,  probably  by  bacterial  action,  a  condition  which 
does  not  detract  from  the  value  of  activated  sludge  as  fertilizer.  When  grease 
extraction  is  considered,  other  processes  than  activated  sludge  are  advisable. 

485  The  activated  sludge  plants  at  Manchester.     (Eng.)     EDITORIAL.    Munic. 
Eng'rg.  &  Sanit.  Record  64,  342-3.     Comments  on  that  part  of  the  report 

of  the  Manchester  Rivers  Committee  for  the  year  ending  March  31,  1919, 
which  deals  with  the  experimental  activated  sludge  plants  installed  at  the 
Withington  and  Davyhulme  sewage  works.  The  Committee  report  that  "the 

82 


Abstract  Bibliography — 1919 

satisfactory  results  previously  obtained  by  the  treatment  of  the  Withington 
sewage  by  the  activated  sludge  process  have  been  well  maintained."  (Cf. 
Ref.  No.  499.) 

486  The  activated  sludge  system.    A  hospital  installation.     ANON.    Surveyor 
56,  293.     Illustration  without  detail  description,  of  an  activated  sludge 

plant  installed  at  the  American  Red  Cross  Hospital  at  Sarisbury  Court,  Eng., 
to  care  for  the  sewage  of  2,000  patients  and  the  staff. 

487  Report  on  the  experimental  treatment  of  sewage  by  the  activated  sludge 
process.     M.    GAULT.     Ann.   Report  Supt.   Sewers,   City   of   Worcester, 

Mass.  For  year  ending  Nov.  30,  1919.  473-549.  An  elaborate  and  detailed 
report  covering  structual  features  of  the  plant,  operating  data,  and  sludge 
dewatering  experiments.  Plant  consisted  of  a  bar  screen,  grit  chamber,  sew- 
age aerating  tank,  sludge  re-aerating  tank,  sedimentation  tank,  and  sludge 
concentrating  tank.  Aerating  tank  was  26.25  by  14  by  10  ft.  deep,  divided  into 
three  channels  each  4  ft.  8  in.  wide,  with  filtros  plates  set  in  7  rows  of  4  plates 
each  across  each  channel  at  3  ft.  9  in.  centers.  A  total  of  84  filtros  plates, 
and  a  diffuser  area  of  1  to  5.2.  Capacity  of  the  tank,  25,283  gallons.  Sludge 
re-aerating  tank  was  12  by  5  ft.  4  in.  by  10  ft.  deep,  divided  into  two  channels 
with  4  rows  of  2  filtros  plates  each  spaced  at  3  ft.  clear  in  each  row.  Capacity 
of  this  tank,  4,386  gallons.  Sedimentation  tank  was  14  ft.  diam.  by  9  ft.  deep, 
with  a  hopper  bottom  tapering  to  2  ft.  diam.  Sludge  concentration  tank  was 
3  ft.  diam.  by  20  ft.  deep,  of  wood,  concrete  lined,  with  a  hopper  bottom 
sloping  to  14  in.  diam.  Sewage  treated  varied  from  75,000  to  125,000  gallons 

rr  day,  aeration  period  from  4  to  6  hours,  sludge  re-aeration  period  from 
to  6.5  hours,  sedimentation  period  from  1.7  to  2.9  hours,  air  flow  1.7  to  5.0 
cu.  ft.  per  gallon  of  sewage,  and  volume  of  sludge  carried  16  to  30%.  Com- 
plete analyses  of  the  air  from  the  sewage  and  sludge  re-aerating  tanks  are 
given,  as  well  as  of  the  sludge  which  averaged  1.94%  solids,  and  contained  on 
a  dry  basis,  51.12  to  71.10%  organic  matter,  8.37  to  17.88%  iron,  3.16  to  7.35% 
N,  and  1.86  to  9.02%  fats.  Numerous  other  tables  of  data  accompany  the 
report,  as  well  as  illustrations.  (Cf.  Ref.  No.  540.) 

488  A  new  process  of  sewage  purification:  oxidation  of  sewage  without  a 
bacterial  bed.    E.  ROLANTS.    Rev.  Hyg.  et  Police  Sanit.  41,  459-78.    Exp. 

Sta.  Record  42,  188.  Chem.  Abst.  14,  2671.  A  review  of  the  work  on  sewage 
purification  by  the  activated  sludge  process. 

489  The  activated  sludge  process  at  Tunstall.     (Eng.)     ANON.    Surveyor  56, 
366.     Illustration  without  detailed  description  of  the  converted  aerating 

tanks  which  are  treating  300,000  gallons  of  sewage  per  day  by  the  activated 
sludge  process. 

490  Treatment  of  sewage  sludge.    G.  MUMFORD.     British  Patent  Application 
30,579,  Dec.  6,  1919.     Jour.  Soc.  Chem.  Ind.  38,  968A. 

491  Results  of  1918  operations  of  the  testing  station  of  the  Milwaukee  Sewer- 
age Commission.    ANON.    Eng.  &  Contg.  52,  669.    Chem.  Abst.  14,  1175. 

It  is  concluded  from  the  report  of  MR.  W.  R.  COPELAND,  Chief  Chemist,  that 
endless  belt  plate  screen  with  slots  1-8  by  2  in.,  with  a  2  in.  loss  of  head,  will 
handle  3  million  gallons  of  sewage  per  24  hours  upon  27  sq.  ft.  of  wetted  area, 
and  remove  150  Ibs.  of  dry  solids  per  million  gallons.  Aerating  tanks  15  ft. 
deep  treated  the  equivalent  of  16.5  million  gallons  of  sewage  per  acre  per  day. 
Tanks  10  and  15  ft.  deep  were  tried,  all  equipped  with  filtros  plates  as  air 
diffusers.  Sludge  and  rust  filled  the  holes  in  perforated  pipes  so  quickly  that 
it  was  necessary  to  empty  tanks  and  clean  the  pipes  after  2  days  run.  Air 
must  be  thoroughly  cleaned.  Dorr  thickeners  proved  successful  in  concen- 
trating the  sludge  in  the  settling  tanks.  Tables  of  analytical  data  are  given. 

492  Present  status  of  the  sew.age  disposal  problem.     G.  G.  NASMITH.     Con- 
tract Record  33,  1137-40.     Can.  Engr.  37,  519-22.     Surveyor  57,  19-21. 

Chem.  Abst.  14,  1173.     General  problems  are  discussed,  chiefly  the  nuisance 

83 


The  Activated  Sludge  Process 

of  sludge  treatment.  Numerous  features  of  the  activated  sludge  process  are 
referred  to,  the  author  stating  that  the  principles  underlying  this  process 
and  trickling  filters  are  identical,  and  that  the  complete  solution  of  the  sewage 
disposal  problem  will  eventually  come  through  a  combination  of  one  of  these 
processes  with  sludge  digestion.  Efforts  to  recover  soluble  nitrogenous  values 
in  sludge  are  made  difficult  by  their  collodial  nature,  and  it  may  be  better  to 
dissolve  and  oxidize  as  much  organic  material  as  possible,  turn  out  a  smaller 
quantity  of  stable  residue,  and  make  no  attempt  at  conservation. 

493  Activated  sludge  plants  in  Texas.     ANON.     Eng.  News-Record  83,  920. 
Besides  the  two  large  plants  at  Houston,  smaller  plants  have  been  put 

in  at  Coleman,  Gainesville,  San  Angelo,  San  Marcos  and  Quanah.  (Also  at 
Sherman,  Paris,  and  Fort  Worth.  J.  E.  P.) 

494  Sewage  purification  problems.     EDITORIAL.    Surveyor  56,  398.     Comment 
on  the  paper  of  MR.  A.  J.  MARTIN  (Ref.  No.  495)  in  which  approval  is 

given  the  suggestion  that  a  central  testing  station  be  established,  in  order  that 
all  new  methods  of  sewage  disposal  may  be  judged  on  their  merits. 

495  Sewage  purification  problems.     A.  J.  MARTIN.     Surveyor  56,  401-2;  419. 
Eng.  &  Contg.  53,  364-5.     Chem.  Abst.  14,  2389.     The  activated  sludge 

process  is  referred  to  as  the  most  promising  novelty  for  the  purification  of 
sewage  which  we  have  had,  and  that  a  way  will  be  found  to  very  materially 
reduce  the  power  now  required  so  that  the  process  will  become  valuable. 
Sludge  dewatering  and  its  use  as  a  fertilizer  is  discussed. 

496  Progress  in  sludge  dewatering  tests.     EDITORIAL.     Eng.  News-Record  83, 
973.     The  work  at  Houston,  Texas,  is  referred  to  (Ref.  No.  497)  but  is 

considered  as  still  in  the  experimental  stage.  If  sludge  dewatering  can  be 
done  practically  and  economically,  it  may  assure  the  success  of  the  activated 
sludge  process  which  produces  a  sludge  of  high  N  content. 

497  Notes  on  the  activated  sludge  plants  at  Houston,  Texas.    ANON.     Eng. 
News-Record   83,   1003-4.     Chem.  Abst.   14,   440.      City   engineer   J.    C. 

McVEA  and  principal  assistant  G.  L.  FUGATE  supply  the  following  data.  The 
north  side  plant,  started  in  May,  1917,  rated  at  10  million  gallons  per  day,  is 
now  treating  5.5  million  gallons  daily.  Plant  cost  $254,671.  South  side  plant, 
started  in  August,  1918,  rated  at  5  million  gallons  per  day,  cost  $115,085.  The 
filtros  plates  when  first  installed  were  held  by  cast-iron  holders,  the  rust  from 
which  clogged  the  plates  so  they  were  removed  and  set  in  concrete.  Washing 
with  hot  HC1  restored  their  porosity  to  nearly  the  original  capacity.  Sludge 
presses  in  operation — two  Simplex  presses  of  120  plates  each — indicate  that 
18,000  Ibs.  of  sludge  of  98.25%  moisture,  can  be  reduced  to  80%  moisture  in 
8  hours.  Addition  of  0.65  gallon  of  66  Be.  sulphuric  acid  per  1000  gallons  of 
sludge  aids  dewatering  and  increases  the  N  content  of  the  sludge  from  5.47 
to  6.93%.  Cost  of  treatment  by  the  activated  sludge  process  is  about  $12  per 
million  gallons,  and  it  is  expected  that  the  revenue  from  the  sludge  will  pay 
the  cost  of  dewatering  and  drying  same,  as  well  as  interest  and  depreciation 
on  the  $85,000  invested.  0.5  ton  of  sludge  per  million  gallons  of  sewage,  and 
a  profit  of  $4  to  $10  per  ton  of  sludge  is  estimated.  10%  moisture  basis.  Sta- 
bility of  effluent  is  obtained  as  long  as  1  p.  p.  m.  of  nitrate  is  present  in  the 
treated  sewage.  The  free  ammonia  results  are  an  index  of  the  condition  of  the 
effluent,  ranging  from  22  p.  p.  m.  in  the  crude  sewage  to  2  p.  p.  m.  in  the  effluent. 
The  latter  is  remarkably  clear.  Removal  of  suspended  matter  is  about  95%. 

498  $6,000,000  sewage  scheme  recommended  for  the  western  part  of  York 
Township,  Ontario,  Canada.     Can.  Engr.  37,  559-60.     Abstract  from  the 

report  of  engineers  FRANK  BARBER  and  R.  O.  WYNNE-ROBERTS.  The  method 
of  treatment  will  be  either  by  means  of  tanks  and  filters  or  by  the  activated 
sludge  process. 

84 


Abstract  Bibliography — 1919 

499  Development   of   the   activated   sludge   process   at   Manchester.      (Eng.) 

ANON.  Surveyor  56,  417-8.  Can.  Engr.  38,  245-7.  Chem.  Abst.  14, 
1400.  Excerpts  from  the  annual  report  of  the  Manchester  Rivers  Dept.  for 
the  year  ending  March  31,  1919.  At  the  Withington  works  172,000  gallons 
per  day  were  handled,  with  air  varying  from  0.8  to  1.7  cu.  ft.  per  gallon  of 
sewage,  and  sludge  varying  from  15  to  30%.  Nitrification  varied  from  0.10 
to  0.65  grain  per  gallon,  the  nitrite  and  nitrate  N  being  calculated  as  am- 
monia. The  tanks  are  6  ft.  deep,  and  the  diif users  therein  have  been  used  for 
2  years  with  a  replacement  of  6  out  of  300.  In  wet  weather  0.8  cu.  ft.  of  air 
maintains  a  good  effluent.  The  plant  works  well  on  varying  rates.  0.5  ton  of 
dry  sludge  is  produced  per  million  gallons:  as  discharged  it  contains  98.8% 
moisture.  Centrifugal  dewatering  has  not  been  encouraging.  At  Davyhulme 
the  fill  and  draw  plant  has  handled  45,000  gallons  per  day.  A  large  plant  is 
under  construction,  comprising  a  grit  chamber,  aerating  tanks,  sludge  reaction 
channel,  and  settling  tanks  of  circular  type  cleaned  by  a  scraper,  and  also  a 
hopper  bottom  type.  This  plant  will  handle  1  million  gallons  per  day  with  6 
hours  aeration,  and  with  2  to  4  hours  re-aeration.  Diffusers  are  one-eighteenth 
tank  area. 

500  Milwaukee    sewage-testing    station:    experimental    data.      ANON.      Eng. 

News-Record  83,  1063.  Surveyor  57,  244.  Chem.  Abst.  14,  439.  Data 
from  the  1918  reports  of  Ch.  Eng.  T.  C.  HATTON  and  Ch.  Chem.  W.  R.  COPELAND. 
Sewage  was  screened  through  Hamburg  type  screens  with  1-8  in.  wide  slots, 
which  protects  the  aeration  tanks  from  coarse  debris  and  enable  the  equiva- 
lent of  16.5  millions  gallons  of  sewage  per  acre  per  day  to  be  treated,  as 
against  7  million  gallons  without  screening.  Suspended  matter  removed  99% ; 
bacteria  removed  95% ;  stability  over  100%  on  their  standard.  The  air  at 
the  plant  is  sooty  and  clogged  the  filtros  plates,  hence  it  was  filtered  through 
a  layer  of  12-oz.  duck  and  then  through  canton  flannel,  which  improved  it. 
Galvanized  iron  pipes  are  preferred  for  air  distribution,  as  black  iron  pipes 
soon  rust  and  the  rust  clogs  the  air  passages. 

501  The  Sanitary  District  of  Chicago.    Stockyards  (sewage)  treatment  plant. 

COMMITTEE  REPORT.  Pamphlet  pp.  32.  (Dec.  1919.)  Reports  of  the 
committee  on  engineering,  the  chief  engineer,  and  the  attorneys,  respecting 
the  treatment  of  sewage  from  the  stockyards  district,  and  the  relations  be- 
tween the  Sanit.  Dist.,  the  packers,  and  others,  concerning  the  construction, 
maintenance,  operation,  and  income  from  a  treatment  plant  suitable  for  the 
purpose.  The  activated  sludge  process  is  favored. 

502  Water  and  sewage   purification.     A.   C.   HOUSTON.     Ann.  Reports  Soc. 
Chem.  Ind.  on  the  Progress  of  Appl.  Chem.  4,  482-5.     The  review  of  the 

activated  sludge  process  for  the  year  1919,  is  confined  almost  exclusively  to 
the  work  at  the  Sheffield  (Eng.)  plant. 

503  Brooklyn,    N.    Y.,    sewage    treatments    experiments.      G.    T.    HAMMOND. 
Trans.  Am.  Soc.  Munic.  Impvts.  26,  98-198.     Eng.  &  Contg.  53,  39.    Fire 

and  Water  Eng'rg.  66,  1278-82.  Refers  in  passing  to  the  activated  sludge  and 
aeration  experiments,  but  an  account  of  this  work  is  reserved  for  a  separate 
paper. 

504  Bureau  of  Sanitary  Engineering.    Municipal  Sanitation.     C.  W.  GODDARD 
and  V.  M.  EHLERS.     Texas  State  Board  of  Health,  publication  No.  3. 

pp.  18.  (1919.)  The  activated  sludge  process  should  be  considered  by  the 
smaller  towns  only  when  very  cheap  power  is  available  and  objections  are 
made  to  other  methods  of  sewage  treatment.  For  larger  cities  where  a  revenue 
can  be  obtained  from  the  sludge,  the  method  may  prove  to  be  the  most  econom- 
ical one.  More  efficient  handling  of  the  sludge  is  desirable.  Comparative 
initial  costs  of  activated  sludge  plants  are  approximated  at  about  one-half 
that  of  a  "Scresetfildis"  plant.  (Screens,  settling,  filtration,  disinfection.) 

85 


The  Activated  Sludge  Process 

505  English  activated  sludge  plants.     ACTIVATED  SLUDGE,  L'TD.     Trade  Cir- 
cular (undated).     Illustrates  and  refers  to  the  following  plants: — Man- 
chester;  Davyhulme  works;   the  fill  and  draw  installation  of  1914,  and  the 
later  continuous  flow  plant;  Withington  works;  plant  treating  250,000  g.  p.  d. 
with  4  hours  aeration  and  82%  purification,  or  375,000  g.  p.  d.  with  3  hours 
aeration  and  81%  purification.     The  Worcester  works,  in  operation  continu- 
ously since  1916,  purifying  750,000  g.  p.  d.     The  plant  at  Stamford  treating 
100,00  g.  p.  d.  of  strong  sewage  containing  much  abattoir  refuse,  with  an 
average  purification  of  90%  by  the  O   absorption  test,  and  of  86%  by  the 
albuminoid  ammonia  test.    A  plant  at  the  National  Filling  Factory  at  Aintree, 
operating  since  1916  on  the  wastes  of  2000  workers.     A  plant  for  the  Ad- 
miralty Airship  Station  at  Moreton;  population  400.     The  experimental  plant 
at  Harpenden  for  H.  M.  Bd.  of  Agr.,  for  producing  activated  sludge  for  fer- 
tilizer tests.     A  plant  for  the  Am.  Red  Cross   Hospital  near  Southampton; 
population  2000.    A  plant  for  a  Gov.  cartridge  factory  at  Blackpole,  completed 
in  1917  and  treating  the  sewage  from  4000  workers.     A  plant  at  Tunstall, 
treating  300,000  g.  p.  d. 

506  Sewage  disposal.    Book.  L.  P.  KINNICUTT,  C.  E.  A.  WINSLOW  and  R.  W. 
PRATT.     Second   Edition,   1919.     Chapter  XII,  pp.   381-405,  deals  with 

the  activated  sludge  process  from  an  historical,  experimental  and  practical 
point  of  view,  discusses  the  results  obtained  at  several  places,  and  gives  a  list 
of  references  to  the  subject. 

192O 

507  Activated  sludge  process  of  sewage   purification.     E.   ARDERN.     Munic. 
Eng'rg.  &  Sanit.  Record  65,  11-2,  26.    Surveyor  57,  8-9.     Chem.  Abst.  14, 

583.  A  review  of  the  experiments  in  England  as  presented  in  an  address  at 
the  meeting  of  the  Assoc.  of  Mgrs.  of  Sewage  Disp.  Works.  At  the  Withing- 
ton works  (Manchester)  there  is  a  tank  of  20,000  gallons  capacity,  capable  of 
treating  45,000  gallons  of  sewage  daily,  also  a  250,000  gallon  plant  with 
aerating  chamber  100  ft.  long,  divided  by  baffles  into  5  channels  each  4  ft. 
wide.  This  plant  could  handle  350,000  g.  p.  d.  Effluents  were  satisfactory, 
purification  quite  good  and  air  consumption  less  than  1  cu.  ft.  per  gallon.  300 
diffusers  have  been  in  use  for  two  years  and  only  8  removed  for  cleaning.  Air 
pressure  is  3.1  Ibs.  Fertilizer  experiments  with  activated  sludge  at  the 
Harpenden  plant  are  referred  to,  and  mention  made  of  the  activated  sludge 
plants  at  Tunstall,  Bury,  for  the  army,  and  some  institutions.  MR.  J.  KERSHAW, 
P.  LAMB,  J.  BOULTON,  W.  H.  MAKEPEACE  and  A.  J.  MARTIN  participated  in 
the  discussion  which  included  such  matters  as  elasticity  of  plant,  effect  of  gas 
liquors  on  the  purification,  mechanical  agitation,  sludge  treatment  and  costs 
of  air  compression. 

508  British  Sanitary  Engineering  developments  in  1919.    EDITORIAL.  Engineer 
129,  10-2.    Eng.  &  Contg.  53,  357-9.     Chem.  Abst.  14,  2524.     Concerning 

the  activated  sludge  process,  it  is  noted  that  despite  the  fact  that  it  has 
had  adverse  conditions  to  contend  with  during  practically  the  whole  of  its 
existance,  it  has  made  a  wonderful  amount  of  headway.  Refers  to  the  new 
experimental  million  gallon  plant  at  the  Davyhulme  works  (Manchester) 
and  a  small  plant  at  Harpenden.  Reading  has  decided  to  treat  the  whole  of 
its  sewage  by  the  activated  sludge  process.  The  results  of  producing  fer- 
tilizer material  from  activated  sludge  are  also  noted. 

509  Bacterial  flora  of  sewage  purified  by  the  activated  sludge  process.     P. 
COURMONT  and  A.  ROCHAIX.     Compt.  rend.  170,  75-8.     Jour.  Soc.  Chem. 

Ind.  39,  171A.  Chem.  Abst.  14,  1400.  The  bacterial  flora  of  samples  of  sew- 
age before  and  after  treatment  by  the  activated  sludge  process  were  studied. 
Aeration  was  carried  out  in  a  small  laboratory  apparatus.  The  total  bac- 
terial reduction  was  considerable;  in  one  sample  the  number  of  organisms 

86 


Abstract  Bibliography — 1920 

was  reduced  from  202  million  per  cc.  to  67,000.  The  bacterial  species  found 
in  the  purified  sewage  were  few  in  number  and  all  aerobic,  chromogenic 
species  predominating.  No  B  coli  were  found. 

510  Record  forms  for  activated  sludge  plants,  Houston,  Texas.    G.  L.  FUGATE. 
Eng.  News-Record  84,  75.     Chem.  Abst.  14,  790.     Daily  report  sheets 

as  used  at  Houston  are  reproduced. 

511  Proposed  activated  sludge  plant  at  Burnley  (Eng.)    NEWS  ITEM.  Surveyor 
57,  27.     A  committee  after  visiting  the  Sheffield  activated  sludge  plant, 

suggest  to  the  Council  that  the  process  be  tried  at  Burnley. 

512  Sixth  Annual  Report  of  the  Milwaukee  Sewerage  Commission.       T.  C. 

HATTON.  Pamphlet  pp.  49,  with  inserts.  (Jan.  15,  1920).  The  report 
of  Ch.  Eng.  Hatton  for  the  year  ending  Dec.  31,  1919,  states  that  the  Com- 
mission unanimously  and  formally  adopted  the  activated  sludge  process.  The 
work  at  the  testing  station  may  be  summarized  as  follows: — Grit  chamber; 
little  information  was  obtained  owing  to  weather  and  sewage  conditions. 
Screens:  chain  belt  screens  with  1-8  in.  and  with  3-32  in.  slots,  sewage  with 
274  to  350  p.  p.  m.  suspended  solids,  head  on  screens  2  to  4  in.,  passed  128,435 
to  246,000  gallons  per  sq.  ft.  of  wet  screen  area,  from  which  472  to  1,017 
Ibs.  of  screenings  of  85  to  87.2%  moisture  were  collected  per  million  gallons 
of  sewage.  Aerating  tanks:  there  was  a  slight  difference  in  favor  of  the 
15  ft.  depth  of  tank,  not  taking  into  consideration  the  extra  cost  of  compressing 
air  for  a  15  ft.  dept  of  liquor  over  that  for  a  10  ft.  depth.  Indications  pointed 
to  easily  treating  12  millions  g.  p.  d.  per  acre  in  10  ft.  deep  tanks,  and  20 
million  g.  p.  d.  per  acre  in  15  ft.  deep  tanks.  155,000  gallons  of  sludge  of 
97.4%  moisture  were  returned  to  the  aerating  tanks  p.  m.  g.  of  sewage 
treated.  Excess  sludge  was  12,100  gallons  of  97.5%  moisture  p.  m.  g.  of 
sewage  treated.  Ratio  of  diffusion  plates  of  1  to  4.4  was  more  favorable 
than  1  to  6.  Contact  period  ranged  from  4  to  6  hours.  Volume  of  air  per 
gallon  of  sewage  was  1.25  cu.  ft.  though  less  could  be  used  but  for  the  agi- 
tating effect  desired.  Experiments  showed  that  owing  to  the  fluctuation  in 
the  character  of  the  sewage,  and  to  prevent  the  light  floculent  sludge  from 
rising  to  the  surface,  that  a  15  ft.  deep  sedimentation  tank  was  necessary, 
and  that  with  this  depth  of  tank,  1,600  to  2,000  gallons  of  mixed  liquor  per 
sq.  ft.  of  tank  area,  could  be  satisfactorily  clarified.  Sludge  re-areation 
tests  do  not  appear  to  justify  the  additional  tankage  and  air  required  for 
the  purpose.  After  one  year's  run  there  was  no  evidence  that  the  filtros 
plates  had  in  any  way  been  reduced  in  porosity  or  stability.  Aif  was 
filtered  through  10  oz.  duck,  then  through  canton  flannel,  and  washed  by 
the  hydro-turbo  blower.  Sludge  pressing  and  drying  investigations  are  still 
in  progress.  Thus  far,  filter  press  experiments  indicate  about  3  Ibs.  of 
sludge  cake  of  80%  moisture  per  sq.  ft.  of  filter  cloth  in  4.5  hours,  from  a 
sludge  containing  initially  97.5%  moisture.  The  report  of  the  Ch.  Chem. 
for  the  year  is  issued  as  a  separate  document. 

513  Treatment  and  disposal  of  sewage.    H.  B.  HOMMON,  J.  K.  HOSKINS,  H. 
W.  STREETER,  R.  E.  TARBETT  and  H.  H.  WAGENHALS.    U.  S.  Public  Health 

Reports  35,  101-31.  Chem.  Abst.  14,  1721.  The  description  of  the  activated 
sludge  process  is  very  brief,  covering  in  short  paragraphs;  theory,  outline  of 
plant,  process,  advantages  and  disadvantages,  and  general.  Under  the  latter 
head  reference  is  made  to  the  proposed  or  existing  plants  at  Milwaukee, 
Chicago  and  Houston,  Texas.  A  bibliography  of  30  references  concludes 
the  article. 

514  Sewerage  and  sewage  disposal.    The  activated  sludge  process.   EDITORIAL. 
Surveyor  57,  75-7.     Reviewing  the  activated  sludge  work  for  the  year 

1919,  reference  is  made  to  the  plant  at  Manchester  (Withington  works) 
where  172,000  gallons  of  sewage  has  been  treated  daily  on  an  average, 
throughout  the  year,  with  an  effluent  of  uniformly  high  purity,  and  with  1 

87 


The  Activated  Sludge  Process 

cu.  ft.  of  air  per  gallon,  except  when  a  high  degree  of  nitrification  was  re- 
quired. Sludge  averaged  0.5  ton  of  dry  matter  p.  m.  g.  sewage.  Reference 
is  also  made  to  the  mechanical  agitation  experiments  conducted  by  MR.  J. 
HAWORTH  at  Sheffield,  Eng.,  and  to  methods  of  sludge  treatment. 

515  Studies  of  methods  for  the  treatment  and  disposal  of  sewage.     L.   C. 
FRANK  and  C.  P.  RHYNUS.     U.  S.  Pub.  Health  Bull  101.    Expt.  Sta. 

Record  43,  189.  Incidentally  refers  to  the  activated  sludge  method  as  among 
those  studied  at  one  time. 

516  The  activated  sludge  process.     TRADE  NOTE.     Surveyor  57,  119.     " — in 
July    last    (1919)    a    limited    company    (Activated    Sludge    Lt'd.)     was 

formed  to  acquire  the  full  control  of  all  patents  held  by  Messrs.  JONES  &  ATT- 
WOOD,  Limited,  of  Stourbridge,  and  others — relating  to  this  process."  AMES- 
CROSTA  apparatus.  "For  several  years  past  the  company  (Ames-Crosta  Sani- 
tary Engineering  Co.,  Lt'd.)  has  devoted  close  attention  to  the  treatment  of 
sewage  by  activated  sludge— and  it  is  hoped  that  an  installation  on  a  large 
scale  of  machinery  of  a  distinctly  novel  character, — will  be  ready  for  in- 
spection in  a  very  short  time." 

517  Sewage  disposal  in  small  cities  and  towns.    M.  F.  STEIN.   Munic.  County 
Eng'rg.  58,   71-5.     Refers   to  the   activated   sludge   process   as   offering 

a  substitute  for  the  Imhoff  tank-trickling  filter  plant,  but  is  more  compact 
and  probably  produces  an  effluent  of  greater  purity.  It  is  largely  on  an  ex- 
perimental basis  at  present.  The  difficulties  of  the  process  are  those  of 
operating  under  the  limitations  of  practical  conditions  as  against  experi- 
mental, and  the  disposal  of  the  sludge. 

518  Modern  sewage  disposal  plant  at  San  Angelo  /Texas.    ANON.  Am.  City  22, 
147-8.     An  activated  sludge  plant  located  less  than  1,000  ft.  from  the 

main  street  of  the  city,  adjoining  a  public  park,  and  operating  only  in  the 
day  time.  Two  old  septic  tanks  110  by  20  by  8  ft.  deep,  and  60  by  20  by  8 
ft.  deep,  were  utilized,  half  of  the  larger  tank  being  converted  into  an  aerat- 
ing chamber,  in  which  the  air  is  distributed  through  perforated  pipes.  The 
other  half  receives  the  raw  sewage  where  it  is  detained  for  about  3  hours 
for  plain  sedimentation.  The  smaller  tank  receives  the  night  flow  of  sewage 
from  which  it  is  injected  to  the  aeration  tank  during  the  following  day. 
A  sludge  settling  tank  20  by  18  by  25  ft.  deep  adjoins  the  aerating  tank. 
Plant  has  a  capacity  of  400,000  g.  p.  d.  but  is  treating  only  225,000  g.  p.  d. 
at  present.  Effluent  is  clear  and  sparkling  with  a  slight  musty  but  not 
offensive  odor,  and  is  discharged  into  a  nearby  river.  Stability  tests  with 
methylene  blue  have  shown  it  to  be  well  within  the  requirements  of  the  law. 

519  The  origin  of  the  activated  sludge  process.    EDITORIAL.   Surveyor  57,  199. 
Eng.  &  Contg.  53,  726.     Chem.  Abst.  14,  2524.     A  consideration  of  the 

claim  of  the  Lawrence,  Mass.,  and  Manchester,  Eng.  workers,  in  which  the 
editor  concludes  that  " — it  is  not  too  much  to  say  that  the  credit  for  the 
development  of  the  laboratory  observations  and  deductions,  and  their  trans- 
lation into  practice,  is  due  entirely  to  the  Manchester  workers." 

520  The  activated  sludge  process.     ANON.    Surveyor  57,  201-2.     Refers  to 
the   report   of   the   Lawrence,   Mass.,   experiment   station   for   the   year 

1917,  (Ref.  No.  362)  quoting  therefrom  on  the  activated  sludge  experiments 
recorded,  and  taking  exception  to  the  "remarkable  American  claim"  that  it 
is  "essentially  a  Lawrence  process." 

521  Sewage  disposal  methods  of  London,  Eng.     ANON.     Surveyor  57,  205. 
Eng.  &   Contg.   53,   762.     Chem.   Abst.   14,   2524.      Statement  that   the 

laboratory  activated  sludge  experiments  after  many  failures  and  adjustments 
gave  sufficiently  successful  results  to  justify  investigation  on  a  practical 
scale.  These  experiments,  undertaken  prior  to  the  war  and  suspended  on 
account  of  it,  are  to  be  revived. 

88 


Abstract  Bibliography — 1920 

522  Glasgow  and   the  acivated  sludge  process.     NEWS   ITEM.    Surveyor  57, 
208     "An  exhaustive  investigation  has  strongly  convinced  a  deputation 

of  the  Glasgow  Corporation  sewage  committee  of  the  value  of  the  activated 
sludge  process."  The  advantages  of  the  process  over  all  other  methods, 
especially  as  to  the  values  recovered  from  the  sludge,  will  result  in  a  recom- 
mendation for  an  activated  sludge  plant  at  Shieldhall. 

523  The  origin  of  the  activated  sludge  process.      EDITORIAL.    Surveyor  57, 
216.     Refers  to  the  opinions  of  the  American  experts,    (Ref.  No.   524) 

and  notes  that  they  agree  with  those  of  the  editor. 

524  The  origin  of  the  activated  sludge  process.     ANON.    Surveyor  57,  222. 
Quotations  from  the  second  edition  of  "Sewage  Disposal,"  pages  282-3, 

by  Kinnicutt,  Winslow  and  Pratt,  from  which  it  may  be  noted  that  DR.  G.  J. 
FOWLER  " ' — to  whom  is  due  the  actual  discovery  of  the  activated  sludge 
process — ' "  admitted  that  " ' — the  illuminating  idea  which  originated  the 
work  was  due  to  the  visit  he  had  paid  while  in  the  United  States  to  the 
Mecca  of  sewage  purification — namely,  the  experiment  station  at  Lawrence 
in  the  State  of  Massachusetts.'  "  "  'Nevertheless,  American  engineers  should 
reciprocate  Dr.  Fowler's  graceful  acknowledgement  by  recognizing  that  none 
of  the  investigations  on  this  side  of  the  water  had  really  brought  sewage 
aeration  to  a  state  of  practical  usefulness.  It  was  the  Manchester  studies, 
and  particularly  the  discovery  of  the  effectiveness  of  previously  aerated  or 
'activated'  sludge  in  promoting  oxidisation,  which  really  gave  us  this  im- 
portant method  of  sewage  purification.'  " 

525  Experience   with    the    activated    sludge    process    at    Manchester    (Eng.) 

ANON.  Eng.  &  Contg.  53,  280-2.  Data  from  the  last  annual  report  of 
the  Manchester  Rivers  Dept.  on  the  fill  and  draw  plant  at  the  Davyhulme 
works,  and  description  of  the  large  continuous  flow  plant  there  under  con- 
struction, also  on  the  plant  at  the  Wellington  works.  (Cf.  Ref.  No.  499). 

526  Fine  screen  specifications  for  the  activated  sludge  plant  at  Milwaukee. 

T.  C.  HATTON.  Eng.  News-Record  84,  511.  Chem.  Abst.  14,  1400.  The 
specifications  call  for  screen  plates  not  less  than  3-16  in.  thick  with  slots 
3-32  in.  minimum  width,  by  2  to  2.5  in.  long.  These  screens  are  for  a  plant 
to  treat  130  million  g.  p.  d.  normal  flow,  and  190  million  g.  p.  d.  storm  flow. 

527  The  activated  sludge  process  of  sewage  purification — large-scale  opera- 
tion.   E.  ARDERN.     Jour.  Soc.  Chem.  Ind.  39,  60-4T.    Surveyor  58,  427-8. 

Chem.  Abst.  14,  1865.  A  large-scale  continuous  flow  plant,  to  replace  the 
experimental  plant  was  installed  for  the  treatment  of  Withington  sewage 
late  in  1917.  A  description  of  the  installation  and  a  general  account  of  the 
results  are  given. 

528  Purification  of  sewage  with  activated  sludge.    R.  CAMBIER.   Compt.  rend. 
170,   681-4.     Jour.   Soc.   Chem.   Ind.  39,   347 A.     Chem.   Abst.   14,   2388. 

Chem.  &  Met.  Eng'rg.  23,  440.  During  the  first  few  minutes  of  contact  of 
raw  sewage  with  activated  sludge,  there  is  a  considerable  reduction  in  am- 
monia without  a  corresponding  increase  in  nitrate  N,  which  shows  a  marked 
increase  only  after  one  hour.  The  phenomenon  is  less  appreciable  if  old 
sludge  is  used,  and  in  this  case,  if  aeration  is  prolonged  excessively,  there 
results  a  decomposition  of  the  sludge  with  production  of  nitrate.  The  effects 
of  aerating  ammonia-free  water  in  the  presence  of  washed  activated  sludge 
for  a  period  of  several  days,  was  to  reduce  its  volume  from  500  to  50  cc.,  and 
to  produce  in  the  liquid  360  mg.  nitrogen  trioxide.  The  sludge  was  found 
to  be  entirely  inactivated.  In  the  presence  of  activated  sludge  nitrification 
is  most  rapid  between  20  and  25  C.  Aeration  for  2  hours  are  required  as 
compared  with  15  hours  at  0  C.  and  4  hours  at  5  C.  Above  30  C.  nitrate 
is  produced  in  very  slight  amounts,  and  at  37  C.  (optimum  temperature  for 
nitrification  in  pure  culture)  only  a  trace  of  nitrate  is  formed  and  there  is 


The  Activated  Sludge  Process 

no  clarification  of  the  sewage.  If  a  mixture  of  activated  sludge  and  sewage 
after  nitrification  is  decanted  after  3  hours,  the  liquid  in  the  interstices  of 
the  sludge  is  found  to  be  considerably  denitrified.  The  nitrifying  capacity 
of  the  sludge,  however,  is  not  effected  thereby.  Both  the  ammonia  and  col- 
liodal  matter  of  the  sewage  are  for  the  most  part  absorbed  by  the  sludge 
at  the  moment  of  contact. 

529  Development  of  sewage  purification.     S.  H.  ADAMS.   Can.  Engr.  38,  314-5. 
In  a  letter  to  the  editor,  reference  is  first  made  to  certain  technical 

journals  raising  the  question  as  to  who  invented  the  so-called  activated  sludge 
process,  followed  by  a  brief  review  of  the  progressive  development  of  sew- 
age purification  for  the  past  30  or  40  years,  noting  the  "air-activation"  work 
of  DR.  CLARK  at  Lawrence  and  DR.  FOWLER  at  Manchester,  and  the  "mechan- 
ical-activation" work  of  MR.  J.  HAWORTH  at  Sheffield,  the  concluding  para- 
graph containing  the  statement  that  " — these  changes  from  land  irrigation, 
chemical  precipitation,  contact  beds  and  sprinkling  filters  to  activated  and 
mechanically  agitated  sludge,  are  but  simple  evolutionary  stages  in  the 
solution  of  a  difficult  problem — ." 

530  Formation  of  activated  sludge.     F.  DIENERT.    Compt.  rend.  170,  762-3. 
Jour.  Soc.  Chem.  Ind.  39,  347 A.     Chem.  Abst.  14,  2229.     In  the  prepara- 
tion of  activated  sludge,  air  is  bubbled  for  a  certain  time  through  sewage, 
which   is   allowed   to   settle,   the   water   drawn   off,   fresh   sewage   added,   air 
again  bubbled  through,  this  being  repeated  until  during  a  period  of  bubbling 
for  5  consecutive  hours,  20  mg.  of  ammoniacal  N  per  liter  of  sewage  is  con- 
verted into  nitrous  or  nitric  N.     Experiments  with  various  samples  of  sewage 
and  water  showed  that  the  time  required  to  produce  activated  sludge  depends 
upon   the   water   employed,   its   temperature,   and   the   quantity   of   air   used. 
Before  being  activated  the  sludge  of  sewage  has  little  if  any  action  upon 
the  water  in  which  it  was  formed.     Analysis  of  water  made  5  days  before 
activation  of  the  sludge  gave  3.0  mg.  per  liter  of  N  as  nitrates  before  aera- 
tion, and  3.7  mg.  after  4  hours  aeration;  the  figures  for  ammoniacal  N  were 
14.9   and   14.0  respectively.     The  day  the   sludge  became  active   the   figures 
were  2.4  and  12.0  mg.  nitrate  N  before  and  after  4  hours  aeration,  and  the 
ammoniacal  N  16.2  and  1.0  mg.  respectively.    Analysis  of  the  sludge  gave  as 
follows:   after  an  aeratoin  period  of  58  days,  but  5  days  before  it  became 
active,  the  total  nitrate  N  was  36.4  mg.  per  gram  of  dry  sludge,  and  the 
ammoniacal  N  1.3  mg.     On  the  day  the  sludge  became  active,  after  an  aera- 
tion  period   of   63   days,  the   figures   were   31.5    and   1.5   respectively.      The 
condition  of  activation  is  reached  abruptly.     In  experiments  with  water  from 
the  tanks  of  the  Pasteur  Inst.,  it  was  proved  that  a  nitrous  fermentation 
took  place  after  the  period   of   activation,  nitrate   N   only   appearing   after 
several  weeks.     During  an  activation  period  of  11  days,  each  time  after  24 
hours  aeration,  all  the  ammonia  introduced   (20  mg.)   was  recovered,  but  on 
the  12th  day  all  the  ammonia  was  transformed  into  nitrites. 

531  Activated  sludge  process  considered  at  London,  Eng.    ANON.  Eng.  News- 
Record  84,  616.    Authority  to  visit  some  of  the  English  activated  sludge 

plants  has  been  requested  by  a  committee,  apparently  to  study  the  process 
with  a  view  of  its  adoption  in  London.  The  volume  of  sewage  discharged 
from  the  two  London  outfalls  is  348,000,000  g.  p.  d.,  and  about  2,000,000 
tons  of  sludge  are  dumped  into  the  sea  annually. 

532  Canada's  first  successful  activated  sludge  sewage  system  at  Brampton, 
Ont.     G.   G.   REID.    Contract  Record  34,  292-7.     Chem.  Abst.  14,  2042. 

In  1908  Brampton  built  a  pair  of  reinforced  concrete  tanks,  each  about  13 
ft.  wide  by  100  ft.  long,  with  covers.  In  1918-19  the  old  tanks  were  con- 
verted into  aeration  chambers  and  a  two-chamber  settling  tank  was  added, 
30  by  16  by  22  ft.  deep  with  two  pockets  at  the  bottom.  Filtros  air  diffusing 
plates  are  used.  The  plant  is  operated  15  hours  per  day,  aerating  at  night. 
(Cf.  Ref.  No.  548). 

90 


Abstract  Bibliography — 1920 

533  Treating  the  waste  of  Packingtown,  Chicago.     LANGDON  PEARSE.    Jour. 
West.  Soc.  Eng'rs.  25,  365-73.    Public  Works  49,  251-3.    Chem.  Abst.  14, 

3489.  A  brief  review  of  the  packinghouse  industrial  waste  problem  in  Chi- 
cago. The  packers  have  agreed  to  pay  60%  of  the  cost.  The  results  of  the 
testing  station  are  briefly  reviewed.  The  activated  sludge  process  proved 
most  practicable,  offering  a  possible  recovery  of  fertilizer  material  and 
grease.  The  plans  recommended  included  intersepting  sewers,  fine  screens, 
aeration  for  8  hours  using  4  cu.  ft.  of  air  per  gallon  of  sewage,  settling, 
handling  the  sludge  with  acid,  filter  pressing  and  rotary  driers.  A  stability 
of  80  to  90%  in  summer  and  30  to  60%  in  winter,  was  obtained  in  the  tests. 

534  Origin  of  the  activated  sludge  process.    H.  W.  CLARK.   Surveyor  57,  308. 
In  a  letter  to  the  editor  Dr.  Clark  quotes  from  published  articles  by  DR. 

FOWLER,  DR.  H.  MACLEAN  WILSON,  ARDERN  &  LOCKETT,  and  from  the  reports 
of  the  Lawrence  Expt.  Sta.,  also  from  correspondence  of  Dr.  Fowler,  in 
support  of  the  author's  contention  that  the  process  originated  at  Lawrence. 
"There  is  no  intention  on  our  part  to  belittle  or  depreciate  the  further  de- 
velopment of  this  process  by  English  workers,  but  in  its  essentials  it  is  a 
Lawrence  process;  and  if,  in  1912,  we  had  not  shown  the  work  then  being 
carried  on  to  Dr.  Fowler,  the  process  would  not  have  been  taken  up  in 
England  for  further  study.  The  gallon  bottles  and  carboys  in  which  this 
process  was  being  carried  on  by  us  in  1912,  and  which  were  shown  to  him, 
were  operated  in  all  essential  details  exactly  as  activated  sludge  tanks  are 
today,  and  producing  equally  good  results,  although  we  had  not  at  that  time 
given  the  process  the  very  attractive  name  afterwards  attached  to  it  by 
the  English  workers." 

535  Action  of  activated  sludges  on  the  ammonia  of  sewage  and  of  ordinary 
water.     F.   DIENERT  and  GIRAULT.     Comptes  rend.  170,  899-901.     Jour. 

Soc.  Chem.  Ind.  39,  382-3 A.  Chem.  Abst.  14,  2670.  The  activated  sludge  pre- 
pared as  previously  described  (Ref.  No.  530)  causes  the  disappearance  of 
ammoniacal  N  from  sewage  and  from  ordinary  water  in  an  almost  identical 
manner,  the  ammoniacal  N  content  of  the  water  having  been  made  equal 
to  that  of  the  sewage.  The  experiments  were  made  by  means  of  allonges  in 
a  water  bath  at  25°  C.,  in  each  of  which  was  placed  450  c.  c.  of  activated 
sludge  containing  about  12  grams  of  dry  matter  at  120°  C.,  and  1500  c.  c. 
of  sewage  or  ordinary  water,  the  ammonia  content  of  each  being  known. 
The  same  amount  of  air  was  made  to  bubble  through  the  mixture  until  the 
ammonia  had  passed  out,  when  the  time  required  for  its  disappearance  was 
noted  and  the  nitrates  and  nitrites  then  determined.  On  each  day  the  liquid 
in  the  two  allonges  was  decanted  and  replaced  by  other  samples  of  the  same 
nature  containing  known  amounts  of  ammonia,  and  the  determinations  re- 
peated. This  was  continued  for  9  months,  the  average  figures  for  each 
month  being  given.  As  the  sludge  gets  older  the  ratio  of  ammonia  oxidized 
to  time  of  disappearance,  at  first  diminishes,  then  increases.  Nitrous  N  only 
appears  after  the  sludge  has  been  used  for  several  months. 

536  Filtros  plates  successfully  cleaned.     G.  L.  FUGATE.     Eng.  News-Record 
84,  754.     Chem.  Abst.  14,  1865.     The  removal  of  iron  rust  from  filtros 

plates  in  the  activated  sludge  plant  at  Houston,  Tex.,  was  accomplished  success- 
fully by  immersing  them  in  HC1  (strength  not  given)  at  98°  C. 

537  The  origin  of  the  activated  sludge  process.    W.  CLIFFORD.    Surveyor  57, 
328.  A  letter  to  the  editor  referring  to  the  letter  of  H.  W.  CLARK  (Ref. 

No.  534)  in  which  the  author  contends  that  "Sufficient  surface  of  slate  or  other 
material  upon  which  abundant  growths  may  occur — is  not  an  essential  condi- 
tion of  the  activated  sludge  process." 

538  The  fertilizing  value  of  sewage  sludges.    W.  E.  BRENCHLEY  and  E.  H. 
RICHARDS.  Chem.  Age.  (Lond.)  2,  404.    Jour.  Soc.  Chem.  Ind.  39,  145R,  177-82T. 
Chem  Abst.  14,  3743.     Results  of  experiments  (pot)  with  activated  and  slate- 

91 


The  Activated  Sludge  Process 

bed  sludges  are  given.  With  1  and  6  units  of  activated  sludge,  barley  showed 
65  and  92%  increase  in  the  weight  of  the  crops  over  that  of  the  control  sample. 
After  barley  had  been  cropped,  mustard  was  sown  in  the  soil  left  in  the  pots, 
the  6-unit  pot  showing  an  increase  of  940%  over  that  of  the  control  sample, 
from  which  the  authors  conclude  that  activated  sludge  may  be  of  considerable 
utility  because  of  the  high  residual  value. 

539  Action  of  the  bacteria  of  sewage  purified  by  the  activated  sludge  process 
on  albuminoid  material,  urea,  and  nitrates.  P.  COURMONT  and  A.  ROCHAIX. 

Comptes  rend.  170,  967-70.  Jour.  Soc.  Chem.  Ind.  39,  423 A.  Chem.  Abst.  14, 
2671.  The  proteolytic  properties  of  the  7  species  of  bacteria  found  in  the 
effluent  from  sewage  purified  by  the  activated  sludge  process  are  either  absent 
or  much  reduced,  according  to  the  reactions  of  these  species  towards  coagulated 
serum,  gelatin,  egg  albumin,  milk  casein,  and  the  production  of  indole.  Five 
of  the  7  gave  indole  following  action  on  peptone,  but  not  upon  the  other 
albuminoid  material  studied.  B.  subtilis  attacks  each  of  the  albuminoid  sub- 
stances yielding  albumoses,  peptones,  leucine  and  tyrosine.  It  secretes  a  rennin 
but  not  casease,  and  it  slowly  attacks  urea.  Three  of  the  7  are  active  in  the 
fermentation  of  urea  and  three  entirely  without  action.  Two  of  the  species 
were  without  action  upon  nitrates  in  bouillon  or  peptone ;  the  other  5  were  direct 
denitrifying  bacteria,  as  shown  by  their  action  on  potassium  nitrate,  some  of 
which  were  very  active. 

540  Activated  sludge  experiments  at  Worcester,  Mass.     RAY  S.  LANPHEAR. 
Eng.  News-Record  84,  819-23.    Chem.  Abst.  14,  1865.     The  experimental 

activated  sludge  plant  consisted  of  a  bar  screen,  grit  chamber,  sewage  aeration 
tank,  sludge  aeration  tank,  sludge  concentrating  tank,  and  a  shallow  tank  for 
measuring  excess  sludge  previous  to  disposal.  The  bar  screen,  0.5"  openings, 
removed  11.4  cu.  ft.  screenings  p.  m.  g.  of  sewage  treated.  At  least  2  cu.  ft.  of 
air  per  gallon  and  4  hours  aeration  was  required  for  weak  sewage  and  3  cu. 
ft.  of  air  and  6  hours  aeration  for  strong  sewage.  Filtros  air  diffusers  were 
used.  Albuminoid  ammonia  must  be  below  2  p.  p.  m.  if  a  stability  of  75%  is 
desired.  The  effluent  was  clear  but  contained  considerable  suspended  matter. 
Dissolved  oxygen  was  low  in  the  effluent  and  nitrification  was  absent.  On 
account  of  the  presence  of  industrial  wastes  and  the  strength  of  the  Worcester 
sewage,  the  process  is  considered  unsatisfactory.  The  sludge  analyzed: — 
total  N,  4.06%,  available  N,  1.39%;  total  phosphorus  pentoxide  2.26%;  citrate 
soluble  1.76%. 

541  Sewage  treatment  plans  for  the  Chicago  Sanitary  District.    ANON.    Eng. 
News-Record  84,  873.     Chem.  Abst.  14,  1865.     The  plans  comprise  the 

following  program: — Construction  of  an  activated  sludge  plant  at  Maywood  to 
abate  the  nuisance  in  the  Des  Plaines  River;  negotiations  for  a  large  activated 
sludge  plant  for  the  stockyards  district  costing  $9.5  million;  also  negotiations 
for  treatment  plants  at  Corn  Products  Co.  and  chrome  tannery  of  Greiss- 
Pfleger  Co.,  and  the  treatment  of  the  sewage  from  the  Calumet  region. 

542  By-products   from   sewage  sludge.     R.   S.   WESTON.     Am.  Jour.  Public 
Health  10,  405-7.     Chem.  Abst.  14,  2041.     Interest  in  fat  and  fertilizer 

recovery  from  sludge  is  renewed  because  of  the  shortage  of  fats  and  fertilizers 
during  the  war,  and  the  discovery  of  the  activated  sludge  and  Miles  processes 
for  sewage  treatment.  Both  of  these  processes  are  briefly  described. 

543  St.  Louis  Meeting  Am.  Chem.  Soc.  Water,  Sewage  and  Sanitation  division. 

ANON.  Jour  Ind.  Eng.  Chem.  12,  419.  Activated  sludge  and  other 
methods  proposed  for  the  treatment  of  sewage,  especially  those  applicable  to 
the  wastes  from  industrial  plants,  was  discussed  at  this  meeting. 

544  Modern  methods  of  sewage  disposal.    E.  S.  CHASE.     Am.  City  22,  485-9. 
A  popular  article  on  the  subject,  referring  to  the  activated  sludge  process 

as  one  with  a  low  first  cost,  requiring  careful  operation,  comparatively  small 

92 


Abstract  Bibliography — 1920 

area,  but  somewhat  more  elaborate  machinery  than  the  older  processes.  It 
produces  a  clear,  sparkling,  colorless  effluent  and  the  bacterial  removal  is  high. 
The  sludge,  if  handled  rapidly,  is  inoffensive  and  has  a  value  as  fertilizer 
material. 

545  Action  of  activated  sewage  sludges.    F.  DIENERT,  F.  WANDENBULKE  and 
M.  LAUNEY.     Comptes  rend.  170,  1089-92.     Jour.  Chem.  Ind.  39,  424A. 

Chem.  Abst.  14,  2670-1.  Experiments  were  made  to  determine  the  influence  of 
varying  amounts  of  activated  sludge  upon  the  rate  of  nitrification  of  Seine 
water  containing  increasing  quantities  of  ammonia.  To  1  liter  samples  of  this 
water  there  was  added  400,  200,  lOOi,  and  50  c.  c.  of  activated  sludge,  correspond- 
ing to  12,  6,  3,  1.5  grams  of  dry  matter  at  1001°  C.  Air  was  bubbled  through  at 
the  rate  of  about  50  liters  per  hour.  Points  determined'  were  the  amount  of 
ammonia  driven  off  and  of  nitric  and  nitrous  N  formed.  Tests  were  made  with 
the  following  amounts  of  ammonia  per  liter:  20  mg.  for  1  hour;  40  mg.  for  1 
hour;  40  mg.  for  2  hours;  60  mig.  for  2  hours;  and  60  mg.  for  3  hours.  By  thus 
varying  the  amounts  of  activated  sludge  and  ammonia  it  was  found  that  the 
ratio  of  ammonia  destroyed  to  the  dry  weight  of  the  sludge  introduced,  dimin- 
ishes as  the  amount  of  sludge  used  increases.  The  results  of  this  process  of 
sewage  purification  were  checked  by  bacterial  counts  upon  different  samples. 
It  rapidly  gives  an  effluent  free  from  ammonia  and  non-putrescible,  but  on  ac- 
count of  the  great  difference  in  the  composition  of  the  various  waters,  the 
reduction  in  the  number  of  bacteria  was  very  variable. 

546  The  nitrogen  in  sewage.    G.  M'GowAN.  Surveyor  57,  405-7.  Eng.  &  Contg. 
53,  736-8.     Chem.  Abst.  14,  3735.     Referring  to  the  activated  sludge  pro- 
cess, the  author  notes  that  the  conservation  in  this  sludge  of  the  more  readily 
assimilable  N  of  the  sewage  colloids  and  solids* — N  which  hitherto  has  been  in 
great  part  lost — should  prove  a  marked  asset  in  its  favor.     Pot  cultures  and 
field  plot  experiments  made  with  it  are  mentioned. 

547  Action  of  the  bacteria  of  the  flora  of  sewage  purified  by  the  activated 
sludge  process  on  carbohydrates.    P.  COURMONT  and  A.  ROCHAIX.   Comptes 

rend.  170,  1134-5.  Jour.  Soc.  Chem.  Ind.  39,  465 A.  Chem.  Abst.  14,  3440.  The 
bacteria  of  the  flora  of  sewage  purified  by  the  activated  sludge  process  exert  a 
marked  fermenting  action  on  carbohydrates.  Varies  with  the  species. 

548  Reconstructed  septic  tanks  serve  as  activated  sludge  plant.    ANON.    Eng. 
&  Contg.  53,  543.     Because  of  the  nuisance,  the  town  of  Brampton,  Ont., 

Can.,  remodeled  a  septic  tank  100  ft.  long  by  carrying  down  one  longitudinal 
wall  about  6  ft.  to  a  horizontal  bottom  about  3  ft.  wide,  a  1  to  1  slope  being 
carried  to  the  opposite  wall.  The  tank  was  also  divided  into  6  sections  by  cross 
walls.  Filtros  plates  in  the  horizontal  bottom  diffused  the  air.  A  settling 
tank  30  by  16  by  22  ft.  deep  was  built  with  2  chambers  which  slope  to  hoppers 
4  by  4  ft.  Surplus  sludge  is  dried  on  outside  beds.  Plant  operates  15  hours 
per  day  with  one  attendant  and  has  received  the  approval  of  the  Provincial 
Board  of  Health.  (Cf.  Ref.  No.  532.) 

549  The  work  of  the  water  and  sewage  laboratory  of  the  Mass.  State  Board  of 
Health.     ANON.     Eng.  &  Contg.   53,   552^3.     At  the  present  time  the 

principal  sewage  studies  at  the  station  are  in  regard  to  the  activated  sludge 
process,  which  is  stated  to  have  had  its  inception  at  Lawrence  in  1912,  in  the 
purification  of  sewage  by  aeration  and  growths. 

550  Results  of  activated  sludge  experiments  at  Milwaukee.    ANON.    Eng.  & 
Contg.  53,  554.    Chem.  Abst.  14,  2388.    Abstract  of  the  Sixth  Annual  Re- 
port of  the  Milwaukee  Sewerage  Commission.     (Cf.  Ref.  No.  512.) 

551  Separation  of  suspended  matters  from  sewage.    ACTIVATED  SLUDGE  LT'D. 
and  COOMBS.  Jour.  Soc.  Chem.  Ind.  39,  434A.     British  patent  application 

No.  13,202,  of  May  13,  1920. 

93 


The  Activated  Sludge  Process 

552  Sewage  purification  plants.    ACTIVATED  SLUDGE  LT'D.  and  COOMBS.    Jour. 
Soc.  Chem.  Ind.  39,  434A.     British  patent  application  No.  13,203,  of  May 

13,  1920. 

553  The  nitrogen  in  sewage.    DISCUSSION.    Surveyor  57,  426-7.    In  discussion 
of  DR.  M'GowAN's  paper  (Ref.  No.  546),  A.  P.  I.  COTTERELL  referred  to 

the  mechanical  agitation  experiments  at  Sheffield,  and  to  the  activated  sludge 
fertilizer  tests  at  Harpenden.  A.  J.  MARTIN  suggested  means  for  aeratnig 
sewage  at  less  cost  and  J.  FIELDHOUSE  related  a  case  where  T.  N.  T.  and 
chemical  wastes  had  injuriously  interfered  with  the  activated  sludge  process. 

554  Activated  sludge  moves  forward.    EDITORIAL.    Eng.  News-Record  84,  989. 
Comment  on  T.  C.  HATTON'S  paper  (Ref.  No.  555),  considering  some  fea- 
tures from  the  practical  point  of  view  that  apply  especially  to  Milwaukee.    The 
activated  sludge  process  is  very  promising  and  it  is  hoped  that  it  may  eventually 
take  a  leading  place  among  the  several  methods  of  sewage  treatment. 

555  Activated  sludge  plant  for  the  city  of  Milwaukee.    T.  C.  HATTON.   Eng. 
News-Recond  84,  990-6.    Public  Works  48,  536-8.    Surveyor  58,  21-3,  48-9. 

Chem.  Abst.  14,  2229.  Plans  are  for  treating  85  million  g.p.d.  in  1930  and  130 
million  g.p.d.  in  1950.  The  plant  will  comprise  bar  screens,  grit  chambers, 
revolving  slotted  fine  screens  3-32",  and  activated  sludge  treatment.  The  bar 
screens  will  be  spaced  3  11-16"  apart.  A  velocity  in  the  grit  chambers  of  from 
0.64  to  1.0  second  feet  is  provided.  The  aeration  tanks  (2)  are  340  ft.  long, 
22  ft.  wide  and  15  ft.  effective  depth,  with  filtros  plates  set  at  right  angles  to 
the  direction  of  flow  and  4.5  ft.  between  centers.  The  sedimentation  tanks  are 
72  ft.  square  and  are  provided  with  Dorr  thickeners.  The  treated  sewage  will 
be  discharged  into  Lake  Michigan  at  14  ft.  depth.  Air  required  is  1.5  cu.  ft. 
per  gallon  of  sewage.  Tanks  15  ft.  deep  are  more  effective  than  those  10  ft. 
deep.  Sulphuric  acid-^4.5  c.  c.  per  gallon  of  sludge — assists  in  dehydrating  it. 
The  sludge  and  screenings  are  to  be  pressed  and  then  dried  in  revolving  driers. 
Coarse  screenings  are  estimated  at  40  Ibs.  p.  m.  g.;  grit  2.3  cu.  ft.;  fine  screen- 
ings at  618  Ibs.  with  87. 2%  moisture,  and  excess  sludge  at  12,100  gallons  p.m.g. 
of  sewage  treated.  Contact  in  the  aeration  tanks  is  based  on  a  6  hour  period. 
The  cost  of  the  plant  is  estimated  at  $5,000,000. 

556  Activated  sludge  experiments  at  Champaign-Urbana,  111.     NEWS  ITEM. 
Eng.  News-Record  84,  1034.     It  is  proposed  to  install  at  first  a  100,000 

g.p.d.  activated  sludge  plant  complete  in  every  particular.  Experiments  will 
be  directed  particularly  to  the  reduction  of  the  amount  of  air  used  and  to 
drying  the  sludge.  The  old  plant  at  Champaign  will  be  utilized  in  part.  DR. 
EDWARD  BARTOW,  Chief  111.  State  Water  Survey,  will  direct  the  work. 

557  The  activated  sludge  process:  Reading's  £148,000  scheme.     ANON.    Sur- 
veyor 57,   440.      The   activated   sludge   process   is   recommended   by   M. 

TAYLOR  as  particularly  suitable  for  Reading,  the  sedimentation  tank  scheme 
held  up  by  the  war,  being  abandoned. 

558  The  progress  of  sewage  disposal.    A.  J.  MARTIN.    Surveyor  57,  446.    A 
popular  lecture  on  the  subject,  in  which  the  activated  sludge  process  is 

briefly  described.  This  new  process  has  been  very  favorably  received,  its  chief 
drawback  being  the  great  bulk  of  the  resultant  sludge  and  the  difficulty  of 
drying  it. 

559  "Forced   Aeration"  sewage  treatment.     ANON.     Public   Works  48,  446. 
Can.  Engr.  38,  522.     As  the  result  of  a  prize  offered  by  Munic.  Eng'rg. 

&  Sanit.  Record  (London)  for  a  new  name  for  the  activated  sludge  process, 
no  less  than  20  were  submitted  from  which  "Forced  Aeration"  was  chosen. 

560  New  Name  for  activated  sludge.    EDITORIAL.    Public  Works  48,  447.    The 
editor  considers  "forced  aeration"  less  descriptive  of  the  activated  sludge 

process  than  the  name  it  would  replace,  and  questions  its  adoption. 

94 


Abstract  Bibliography — 1920 

561  Purification  of  sewage  and  other  liquids.     W.  JONES,  Stourbridge,  Eng. 
U.  S.  Patent  1,341,561,  May  25,  1920.     (Application  filed  Aug.  8,  1919. 

4  claims.)  Off.  Gaz.  274,  755.  Jour.  Soc.  Chem.  Ind.  39,  526 A.  Claim  1:— 
In  a  purification  system,  a  tank  divided  into  a  plurality  of  communicating 
open  chambers,  and  an  air  supply  for  each  chamber,  the  walls  of  the  chamber 
being  formed  to  direct  the  flow  of  the  liquid  under  the  pressure  of  the  air 
supply  in  a  circulatory  path  within  the  chambers.  (Cf.  Brit.  Pat.  132,826, 
Ref.  No.  404.) 

562  Tunstall  activated  sludge  plant.    NEWS  ITEM.     Surveyor  57,  469.     At  a 
meeting  of  the  Midland  District  of  the  Assoc.  of  Mgrs.  of  Sewage  Dis- 
posal Works,  held  at  Tunstall,  the  activated  sludge  plant  was  inspected,  the 
process  being  explained  in  detail  by  the  sewage  engineer,  W.  H.  MAKEPEACE. 

563  Purification  of  sewage  by  activated  sludge.    R.  CAMBIER.    Comptes  rend. 
170,  1417-9.     Jour.  Soc.  Chem.  Ind.  39,  525A.     A  very  slight  trace  of 

chloroform  in  the  air  bubbled  through  the  sewage  during  treatment  by  the 
activated  sludge  process  is  sufficient  to  inhibit  the  formation  of  nitrates.  Sim- 
ilarly, if  air  saturated  with  chloroform  is  bubbled  through  the  sewage  for 
one  hour,  and  then  pure  air  for  four  hours  to  remove  the  chloroform,  on  the 
introduction  of  the  sludge  and  the  subsequent  bubbling  of  air,  the  ammonia 
disappears,  but  no  nitrates  are  formed.  Further,  attempts  to  isolate  nitrifying 
organisms  from  activated  sludges  were  not  successful.  These  results  are 
opposed  to  the  view  that  nitrification  takes  place  during  the  purification  of 
sewage  by  the  activated  sludge  process. 

564  Sewage  effluents  for  disposal  with  and  without  dilution.     ANON.    Eng. 
News-Record   84,   1161-2.     Chem.   Abst.    14,   2960.      From   a   report   on 

sewage  works  operation  submitted  to  the  Sanit.  Eng.  Sec.,  Am.  Pub.  Health 
Assoc.  in  Oct.,  1919.  The  normal  characteristics  of  activated  sludge  effluents 
as  produced  experimentally  are  as  follows: — "(1)  Low  total  suspended  solid 
matter.  (2)  A  practical  absence  of  settleable  suspended  matter.  (3)  Presence 
of  oxidized  nitrogen  as  nitrites  or  nitrates  in  amounts  equivalent  to  or  better 
than  in  sprinkling  filter  effluents.  (4)  A  low  oxygen  demand.  (5)  A  high  re- 
duction in  total  bacteria  content."  The  importance  of  skilled  supervision  for 
practical  activated  sludge  plants  is  emphasized. 

565  Separation  and  settlement  of  solid  matters  from  sewage  and  other  liquids. 

WM.  CLIFFORD,  Oxley,  Wlolverhampton,  Eng.  U.  S.  Patent  1,343,764 
June  15,  1920.  (Application  filed  March  27,  1918.  2  claims.  Assigned  to 
JONES  &  ATTWOOD,  L'TD.,  Amblecote,  Eng.)  Off  Gaz.  275,  539.  Chem.  Abst.  14, 
2388.  Claim  1: — A  settling  tank,  an  inflow  pipe,  a  guard  about  the  delivery 
end  of  said  pipe  and  comprising  a  cylindrical  casing  of  uniform  diameter 
throughout  with  open  ends  above  and  below  said  inflow  pipe,  and  a  vessel 
closed  at  the  bottom  and  open  at  the  top  arranged  centrally  within  and  wholly 
above  the  lower  end  of  the  guard,  the  inflow  pipe  directing  the  material  into 
the  open  end  of  said  vessel.  (Cf.  Brit.  Pat.  117,472,  Ref.  275.) 

566  Aeration  of  sewage  and  other  impure  liquids.    OSWALD  STOTT,  Birming- 
ham, Eng.,  and  ERNEST  R.  JONES,  Stourbridge,  Eng.   U.  S.  Patent  1,343,- 

797,  June  15,  1920.  (Application  filed  June  21,  1919.  6  claims.)  Off.  Gaz.  275, 
546..  Jour.  Soc.  Chem.  Ind.  39,  557 A.  Chem.  Abst.  14,  2388.  Claim  1:— In  a 
process  of  purifying  sewage  and  other  impure  liquids  in  which  the  purification 
is  effected  by  bacterial  sludge  and  air,  artificially  crculating  the  sewage  or 
liquid,  and  at  the  same  time  ruffling  or  agitating  the  surface,  so  as  to  cause 
the  introduction  of  air  into  the  liquid  by  said  ruffling  or  agitation.  (Cf.  Brit. 
Pat.  133,722,  Ref.  No.  407.) 

567  Activated  sludge  plant  at  California  State  Prison.     ANON.     Eng.  News- 
Record  84,  1260.    The  activated  sludge  plant  at  the  Folsom  State  Prison 

has  served  a  population  of  about  1500  for  two  years  with  excellent  results, 

95 


The  Activated  Sludge  Process 

though  operated  by  convict  labor  that  is  very  unreliable.  Air  diffusion 
through  perforated  pipes  has  given  almost  no  trouble.  The  activated  sludge 
plant  proposed  for  Hermosa  Beach  has  never  been  constructed,  hence  the  Fol- 
som  plant  is  the  only  activated  sludge  plant  in  California. 

568  The  treatment  of  sewage — activated  sludge  system,  Folly  Point,  Sydney. 

ANON.  Commonwealth  Eng.  7,  330-2.  Chem.  Abst.  14,  2833.  Because 
increased  volume  of  sewage  made  plant  additions  necessary,  the  activated 
sludge  system  was  adopted  instead  of  installing  additional  septic  tanks.  Both 
septic  tanks  and  the  activated  sludge  system  are  in  use  at  the  present  time. 

569  Stream  pollution  in  Illinois.     LANGDON  PEARSE.     Jour.  Am.  Waterworks 
Assoc.  7,  549-52.    Chem.  Abst.  14,  2833.    Refers  to  the  proposed  activated 

sludge  plant  for  treating  packinghouse  wastes  in  Chicago,  the  experiments  on 
tannery  and  corn-products  wastes,  and  to  the  ultimate  treatment  of  all  sewage 
in  the  entire  Sanitary  District  of  Chicago. 

570  Purification  of  sewage  by  activated  sludge.    R.  CAMBIER.     Comptes  rend. 
171,  57-60.    Chem.  Age  (Lond.)  3,  76.    Jour.  Soc.  Chem.  Ind.  39,  556-7 A. 

The  ferrous  sulphide  normally  present,  or  artificially  introduced,  into  sludges, 
appears  to  be  an  important  factor  in  the  purifying  and  nitrifying  action  of 
these  sludges  on  sewage.  It  is  frequently  noticed  that  when  such  sludges 
lose  their  activity  a  reddish  color  due  to  ferric  hydroxide  is  apparent.  All  the 
causes  which  tend  to  destroy  the  ferrous  sulphide,  or  modify  its  physical 
state,  equally  tend  to  destroy  the  activity  of  the  sludge.  It  was  found  that 
sludges  which  had  become  practically  inactive  could  be  re-activated  by  the 
addition  of  either  ferrous  sulphide  or  of  equimolecular  proportions  of  solu- 
tions of  ferrous  sulphate  and  ammonium  sulphide. 

571  London  County  Council's  large-scale  experimental  works.     ANON.     Sur- 
veyor 58,  23.     Chem.  Abst.   14,  3735.     At  the  southern  outfall  works, 

lime-water  tanks  at  present  out  of  use,  are  to  be  equipped  for  activated  sludge 
experiments  capable  of  treating  250,000  g.  p.  d.  One  tank  is  to  be  equipped 
on  the  principle  adopted  at  Manchester  and  Worcester, — air  agitation — and 
one  on  the  plan  adopted  at  Sheffield, — mechanical  agitation. 

572  A  sewage  farming  possibility.    EDITORIAL.    Eng.  News-Record  85,  145-6. 
Refers  to  possible  use  of  Los  Angeles,  Calif.,  sewage  for  land  irrigation, 

and  suggests  that  the  activated  sludge  process  as  a  preliminary  treatment 
might  be  worth  looking  into.  The  Pasadena  activated  sludge  experiments  are 
referred  to  as  a  near-by  source  of  information. 

573  Activated  sludge  exhibit.     NEWS  ITEM.     Surveyor  58,  64.     Chem.  Age 
(Lond.)  3,  133.    At  the  Health  exhibition  of  the  Royal  Sanitary  Institute 

Congress  held  at  Birmingham  (Eng.)  in  July,  1920,  an  exhibit  of  the  activated 
sludge  process  attracted  much  attention. 

574  Some  points  to  observe  in  the  design  of  sewerage  systems  and  disposal 
works.     THEO.   HORTON.     Munic.  &  County  Eng.rg.     59,   58-9.     While 

conceding  the  activated  sludge  process  to  be  practical,  it  seems  to  have  some 
inherent  features  which  are  difficult  to  control,  and  it  is  therefore  not  being 
very  generally  adopted. 

575  Proposed  sewerage  and  water  supply  scheme   for  Port  Colborne,  Ont., 
Canada.    ANON.    Can.  Engr.  39,  269.    For  this  town  of  4,000  population 

R.  O.  WYNNE-ROBERTS  recommends  the  activated  sludge  process  of  sewage 
treatment. 

576  The  design  of  Cleveland's  sewage  treatment  works.     G.  B.  GASCOIGNE. 
Eng.  News-Record  85,  344-9.     Chem.  Abst.  14,  3488.     A  consideration  of 

the  different  plants  proposed  and  reference  to  the  activated  sludge  investiga- 
tions made. 

96 


Abstract  Bibliography — 1920 

577  Sewerage  and  water  developments  at  Decatur,  111.    ANON.    Eng.  News- 
Record  85,  457-8.     Chem.  Abst.  14,  3487.     During  1917  small  scale  tests 

were  made  with  the  activated  sludge  process  on  mixed  industrial  and  domestic 
sewage,  and  in  1919  the  activated  sludge  process  was  tried  on  crude  starch 
waste  alone.  The  process  was  found  applicable  in  the  first  case  but  not  in  the 
latter.  The  normal  city  sewage  consists  of  a  mixture  of  about  4,250,000  gal- 
lons of  domestic  and  1,250,000  gallons  of  industrial  sewage  daily.  Decision 
has  not  been  made  as  to  the  type  of  treatment  plant. 

578  Sewage  disposal.     C.  H.  GODFREY.     Munic.  Gaz.   (Shanghai),  13,  317-8. 
Surveyor  58,  292.    A  report  of  the  author's  visit  to  India  and  Burmah. 

When  treating  sewage  by  the  activated  sludge  process  it  is  important  to 
break  up  the  solids  or  remove  as  much  of  them  as  possible  by  screens.  The 
mechanical  agitations  experiments  at  the  Sheffield  activated  sludge  plant  are 
referred  to. 

579  Relation  of  chemical  engineering  to  sewage  and  trade  waste  treatment. 

R.  H.  EAGLES.  Chem.  &  Met.  Eng'rg.  23,  438-40.  The  activated  sludge 
process  is  briefly  described,  with  special  reference  to  the  various  means  of  air 
diffusion.  Attention  is  directed  to  the  common  use  of  air  far  in  excess  of 
theoretical  requirements.  The  use  of  the  Dorr  thickener  for  sludge  concen- 
tration and  problems  in  connection  with  its  dewatering  and  drying  are  also 
discussed.  The  Dorr  company's  activated  sludge  plant  at  Mt.  Vernon,  N.  Y., 
is  mentioned. 

580  A  novel  laboratory  for  industrial  research.    ANON.    Chem.  &  Met.  Eng'rg. 
23,  496-8.    Refers  to  the  Westport  mill  of  the  Dorr  Co.     Their  modifica- 
tion of  the  activated  sludge  process  is  very  briefly  described.     After  passing  a 
revolving  screen  the  sewage  is  aerated  in  a  specially  designed  thickener  which 
affects  distribution  and  circulation  of  the  air  bubbles  in  one  chamber,  and 
causes  sedimentation  in  another  chamber.     The  indications  are  that  aeration 
may  thus  be  accomplished  in  less  time  and  at  less  cost  than  by  other  means,  as 
less  air  is  used.     Research  work  on  biological  sludge  treatment  is  in  progress. 

581  Activated  sludge  experiments  at  Mt.  Vernon,  N.  Y.    R.  H.  EAGLES.    Eng. 
News-Record  85,  490-2.     Chem.  Abst.  14,  3488.     45,000  gallons  of  rather 

strong  domestic  sewage  are  treated  daily,  first  passing  a  0.75"  bar  screen.  The 
plant  proper  consists  of  a  "Dorrco"  rotary  screen  and  two  combination  aeration- 
sedimentation  tanks  in  series,  each  12  ft.  in  diameter  by  11  ft.  deep,  with  a 
total  capacity  of  17,600  gallons.  Aeration  occurs  in  the  lower  compartment 
where  the  liquid  depth  is  6.5  ft.,  air  being  diffused  through  filtros  plates.  Ap- 
proximately 75%  of  the  air  used  is  introduced  into  the  first  unit  and  25%  in 
the  second.  Sedimentation  takes  place  in  the  upper  compartment.  Purifica- 
tion is  effected  by  0.6  cu.  ft.'  of  air  per  gallon  of  sewage,  with  an  aerating 
period  of  8  to  10  hours.  Effluent  is  clear,  colorless,  contains  less  than  20 
p.  p.  m.  of  suspended  solids  (initially  245  p.  p.  m.),  up  to  1  p.  p.  m.  nitrate 
and  nitrite  N,  and  is  stable  at  least  4  days  by  the  methylene  blue  test.  90% 
of  the  bacteria  is  removed  and  the  O  consumption  reduced  79.6%  (initially 
154  p.  p.  m.)  The  dry  sludge  has  7  to  9%  N  as  ammonia.  Some  tabulated 
data  are  given. 

582  Sewage  disposal  research  work.     NEWS  ITEM.     Surveyor  58,  188.     The 
Ministry  of  Health  have  investigated  the  results  of  the  activated  sludge 

process  at  various  locations  and  is  continuing  the  work.  The  use  of  sewage 
sludge  as  fertilizer  has  also  been  investigated  in  co-operation  with  the  Min- 
istry of  Agriculture  and  Fisheries. 

583  Reading  (Eng.)  sewage  disposal.    NEWS  ITEM.   Surveyor  58,  221.    Eng. 
News-Record  85,  833.     Authority  to  borrow  the  necessary  funds  for  the 

building  of  an  activated  sludge  plant  capable  of  treating  the  entire  sewage 
of  the  city  has  been  given.  The  plans  have  been  prepared  by  G.  M.  TAYLOR. 

97 


The  Activated  Sludge  Process 

584  Disposal  of  waste.    F.  W.  PARSONS.    Saturday  Eve.  Post.  193,  36-8.    A 
popular  article  on  sewage  disposal  practice,  with  particular  reference  to 

the  Milwaukee  activated  sludge  plant,  illustrating  the  2  million  g.  p.  d.  plant 
built  in  1917. 

585  Peterboro  favors  Imhoff  tanks,  Municipal  Board  orders  activated  sludge. 

NEWS  ITEM.  Can.  Engr.  39,  410.  Because  the  Ontario  Board  of  Health 
refuses  to  permit  the  discharge  of  Imhoff  tank  effluent  into  a  river,  the  Munici- 
pal Board  says  an  activated  sludge  plant  must  be  installed,  notwithstanding  a 
favorable  report  on  the  Imhoff  tank  process  by  the  city  council. 

586  The  activated  sludge  process.    EDITORIAL.   Surveyor  58,  225.    Can.  Engr. 
39,  627-8.    Refers  to  the  approval  of  the  Reading  (Eng.)  activated  sludge 

scheme  by  the  Ministry  of  Health  as  an  official  endorsement  of  the  process, 
and  briefly  summarizes  the  progress  which  the  process  has  made  since  1914. 
It  is  concluded  that  the  activated  sludge  process  has  now  definitely  emerged 
from  the  experimental  stage. 

587  North  Shore  Sanitary  District's  sewage  disposal  problem.    W.  J.  ALLEN. 
Fire  &  Water  Eng'rg.  68,   (Oct.  13,  1920).     Aeration  strongly  advised, 

with  thickening  machines  suggested  as  a  method  of  separating  the  sludge  from 
the  liquid. 

588  Activated  sludge  process  at  Sydney,  Australia.  J.  W.  SMAIL.   Ann.  Report 
Met.  Board  of  Water  Supply  and  Sewage.     (1919-20.)     Jour.  Inst.  Munic. 

&  County  Engrs.  ?  Eng.  News-Record  85,  780.  Six  activated  sludge  tanks 
displace  septic  tanks,  three  of  which  are  in  operation  treating  900,000  g.  p.  d. 
on  the  fill  and  draw  plan,  12  hour  cycle.  7  hours  aeration,  2  hours  settling,  1 
hour  decanting,  2  hours  sludge  re-aeration.  Centrifugal  sludge  dewatering 
experiments  are  in  progress. 

589  Am.  Soc.  Munic.  Impvts.    St.  Louis  Meeting,  1920.    ANON.    Eng.  News- 
Record  85,  815.     Public  Works  49,  385-7,  461-3.     The  advances  in  the 

activated  sludge  process  were  brought  out  by  the  papers  of  LANGDON  PEARSE 
and  PROF.  E.  BARTOW,  and  in  the  discussion  following.  A  description  of  the 
Argo,  111.  plant,  of  the  Chicago  stockyards  plant,  and  a  brief  history  of  the 
activated  sludge  work  of  the  Chicago  Sanit.  Dist.  was  given  by  Mr.  Pearse. 
Prof.  Bartow's  paper  on  the  present  status  of  the  activated  sludge  process 
reviewed  recent  work  and  described  the  new  experimental  plant  at  Urbana, 
111.  T.  C.  HATTON  reported  the  total  cost  of  operating  the  Milwaukee  plant 
as  $35  p.  m.  g.,  with  credit  for  sludge  values  of  $18,  or  a  net  cost  of  $17  p.  m.  g. 
of  sewage  treated.  J.  C.  McVEA  stated  that  the  cost  of  operating  the  Houston 
activated  sludge  plant  was  $14  p.  m.  g.,  exclusive  of  overhead  and  sludge 
treatment.  Sludge  handling  methods  were  discussed.  The  process  as  yet  is 
applicable  only  in  special  cases. 

590  Ter  Meer  sludge  dewaterer  at  Milwaukee.    ANON.    Eng.  News-Record  85, 
889.     This  is  a  centrifugal  machine  of  German  make  under  trial  at  the 

activated  sludge  plant.  Preliminary  tests  gave  a  4  inch  cake  and  thus  far  the 
machine  is  giving  a  satisfactory  product.  Because  the  sludge  varies  greatly 
between  winter  and  summer  as  to  colloid  content,  filter  press  operation  seems 
uncertain. 

591  Activated  sludge  in  England.     EDITORIAL.     Eng.  News-Record  85,  1018. 
Comment  on  the   approval  of  the   activated   sludge  plant  for  Reading 

(Eng.)  by  the  Ministry  of  Health.  "*  *  *  the  adoption  of  the  activated 
sludge  process  for  all  the  sewage  of  so  large  a  British  town  (nearly  100,000 
pop.)  is  something  that  may  well  be  noted  by  American  engineers." 

592  The  disposal  of  trade  wastes.     R.  S.  WESTON.     Public  Works  49,  504-6. 
A  general  description  of  the  nature  and  origin  of  various  trade  wastes 

98 


Abstract  Bibliography — 1920 

and  their  effects  in  sewage,  referring  to  the  activated  sludge  process  only  in 
connection  with  its  failure  to  successfully  purify  the  sewage  at  New  Haven, 
because  of  the  poisonous  nature  of  the  copper  salts  present. 

593  Activated  sludge.    EDITORIAL.    Surveyor  58,  374.    Comment  on  the  report 
of  W.  H.  MAKEPEACE  on  the  Tunstall  activated  sludge  plant.     (Ref.  No. 

595.)  The  process  is  shown  to  be  entirely  satisfactory  from  every  point  of 
view,  including  both  construction  and  maintenance  costs.  The  suggested  re- 
quirements for  a  complete  scheme  of  activated  sludge  treatment  should  be 
useful  to  other  engineers. 

594  Sewage  disposal  at  Manchester,  (Eng.)     ANON.    Surveyor  58,  375.    Ex- 
tracts from  the  annual  report  of  the  Rivers  Dept.  for  the  year  ending 

March  31,  1920.  The  fill  and  draw  activated  sludge  plant  at  Davyhulme  has 
operated  throughout  the  year,  receiving  3  or  4  fillings  per  day  with  an  aerating 
period  of  4  to  5  hours.  The  large  continuous  flow  plant  has  been  completed 
but  is  not  yet  in  service  because  of  delays  in  obtaining  operating  equipment. 
Research  during  the  year  has  been  confined  almost  exclusively  to  activated 
sludge  investigations,  including  experiments  on  the  acceleration  of  sludge 
settlement  by  means  of  tank  design,  acid  and  various  electrolytes;  dewatering 
the  sludge  by  filter  pressing  and  centrifuges,  the  latter  being  the  most  promis- 
ing; tests  relating  to  aerating  tank  design,  from  which  it  appears  that  the 
length  of  travel  through  the  tank  is  not  as  important  as  first  thought,  pro- 
vided thorough  admixture  of  sludge  and  sewage  is  effected,  and  a  prolonged 
investigation  of  the  N  content  of  the  sludge  in  relation  to  that  of  the  sewage 
treated,  the  results  of  which  should  be  available  for  publication  shortly. 

595  Activated  sludge  experiments  at  Tunstall.     ANON.     Surveyor  58,  380. 
Extracts  from  the  report  of  W.  H.  MAKEPEACE,  sewage  engineer,  which 

is  summarized  as  follows : — "*  *  *  it  marks  a  distinct  advance  in  the  meth- 
ods of  treating  sewage  and  possesses  many  possibilities  over  the  other  types. 
It  is  reliable  when  once  established.  It  is  not  likely  to  be  interfered  with  by 
trade  wastes  of  our  district.  It  is  considerably  less  costly  to  construct.  It 
certainly  would  be  less  costly  to  maintain  than  our  existing  plants.  It  causes 
no  aerial  nuisance  under  the  worst  conditions.  It  is  controlled  by  a  much 
smaller  though  more  skilled  staff.  It  can  often  be  applied  without  a  pumping 
scheme.  The  resultant  sludge  possesses  higher  fertilizing  value  than  the 
sludge  from  existing  plants.  The  sludge  is  not  offensive.  Portions  of  our 
existing  plants  can  be  readily  adapted  to  the  fill  and  draw  method.  It  com- 
plies easily  with  all  the  requirements  of  the  Royal  Com.  recommendations." 

596  Large  activated  sludge  installation  at  Reading,  Eng.    ANON.    Eng.  News- 
Record  85,  1125.     Plant  designed  to  ultimately  handle  4,200,000  g.  p.  d. 

and  will  be  the  largest  activated  sludge  plant  in  England.  Will  comprise 
screens,  detritus  chambers,  4  aeration  tanks  with  a  total  capacity  of  2,100,000 
gallons,  2  settling  tanks,  total  capacity  540,000  gallons,  sludge  storage  tanks 
of  180,000  gallons,  and  a  re-aeration  tank  of  312,000  gallons.  (All  U.  S.  gal- 
lons.) 

597  Houston  activated  sludge  plant  results.     ANON.    Eng.  News-Record,  85, 
1128.    As  given  by  J.  C.  McVEA,  city  engineer,  at  the  St.  Louis  meeting, 

Am.  Soc.  Munic.  Impvts.  One  plant  is  handling  a  little  more  than  6  million 
g.  p.  d.,  the  other  about  1  million.  Total  air  used  is  1.44  cu.  ft.  per  gal.  of 
sewage  treated,  divided  0.94  cu.  ft.  in  the  aerating  tanks,  0.44  cu.  ft.  in  the 
re-aerating  channels  and  0.06  cu.  ft.  for  the  air  lifts.  Average  aerating 
period  is  2.25  hours.  Re-aerating  sludge  4  hours  40  min.  Suspended  solids 
are  reduced  96-98%,  O  consumed  50  to  84%,  relative  stability  about  98%. 
The  effluent  is  clear  and  unoffensive. 

598  The  Des  Plaines  River  activated  sludge  plant.    LANGDON  PEARSE.    Eng. 
News-Record  85,  1134-8.    This  plant  is  under  construction  at  Riverside, 


The  Activated  Sludge  Process 

111.,  by  the  Sanit.  Dist.  of  Chicago.  It  is  designed  to  care  for  the  sewage  from 
a  population  of  over  30,000  and  with  a  wide  flexibility  for  practical  and  experi- 
mental purposes.  Coarse  bar  screens  are  followed  by  a  two-compartment  grit 
chamber,  each  compartment  being  47  by  3.5  by  3  ft.,  and  this  by  a  Riench-Wurl 
screen  14  ft.  in  diameter.  Four  aerating  tanks  are  provided,  all  126  ft.  long 
inside.  One,  21  ft.  wide  by  15  ft.  deep,  and  one,  30  ft.  4  in.  wide  by  10  ft.  deep, 
both  baffled  once  longitudinally,  will  be  used  as  straight  flow  tanks.  One,  10 
ft.  deep,  divided  by  baffles  into  4  longitudinal  channels  each  7  ft.  7  in.  wide, 
will  treat  sludge  re-aerated  during  its  return,  and  another  of  the  same  dimen- 
sions and  design  will  be  run  with  sludge  re-aerated  and  settled  before  re-use. 
All  aerating  tanks  have  ridge  and  furrow  bottoms  with  filtros  plates  in  con- 
crete containers  in  the  furrows.  Ratio,  1  to  5.7,  to  1  to  5.9.  Settling  tanks 
with  hopper  bottoms  and  others  with  Dorr  thickeners  are  provided,  with  air 
lifts  for  handling  the  sludge.  For  sludge  concentration  or  storage  6  tanks 
15  ft.  square  by  11.5  ft.  deep  are  provided.  Filter  presses,  a  centrifuge  of  the 
Ter  Meer  type  and  a  direct-indirect  dryer  are  to  be  used  for  sludge  handling. 
Cloth  screens  and  a  hydroturbine  blower  will  supply  clean  air. 

599  Tunstall  activated  sludge  experiments.    W.  H.  MAKEPEACE.    Surveyor  58, 
397-8.     The  plant  comprises  a  detritus  tank  21  by  9  by  5.5  ft.  deep  of 

6,700  gallons  capacity,  aerating  tanks  (converted  filter  plant)  75  by  42  ft.  9 
in.  with  semi-circular  ends  and  average  depth  of  7  ft.  9  in.,  of  156,875  gallons 
capacity,  divided  into  10  chambers;  sedimentation  tank  25  ft.  diam.  by  13  ft. 
10.5  in.  deep  of  42,500  gallons  capacity.  Aerating  tank  floor  is  on  the  ridge 
and  furrow  plan  with  porous  tile  diffusers  at  the  bottom  of  the  furrows. 
300,000  g.  p.  d.  are  treated  on  the  continuous  flow  plan.  The  plant  was  sub- 
jected to  abuses  likely  to  arise  in  practice  and  stood  all  the  tests  satisfactorily. 
"*  *  *  it  is  a  vast  improvement  and  advance  on  any  known  method,  not 
only  for  its  thoroughness,  but  for  its  more  hygenic  methods  during  treatment." 

600  Notes  on  sludge  disposal.    J.  E.  FARMER.    Surveyor  58,  412.     With  re- 
spect to  activated  sludge,  it  is  suggested  that  the  liquid  sludge  be  pumped 

directly  onto  the  land  to  be  fertilized.  Laboratory  experiments  show  that  the 
odor  of  ordinary  sewage  sludge  is  changed  to  an  earthy  smell  if  treated  by 
aeration  as  in  the  activated  sludge  process,  and  that  there  is  no  loss  of  N. 
In  the  discussion,  (p.  430)  C.  H.  BALL  stated  that  a  "drying  tank"  to  deal  with 
5,000  tons  of  activated  sludge  per  annum  was  being  installed  at  Manchester. 

601  Assoc.  of  Managers  of  sewage  disposal  works.  General  meeting  in  London. 

ANON.  Surveyor  58,  413-4.  Excerpts  from  the  presidential  address  of 
A.  J.  MARTIN,  in  which  reference  is  made  to  the  Worcester  and  London  acti- 
vated sludge  experiments,  to  the  proposed  plant  at  Milwaukee,  and  that  of  the 
Chicago  Sanit.  Dist.  in  the  stockyards.  Also  to  DR.  G.  McGowAN's  paper  on 
the  nitrogen  in  sewage.  "The  outstanding  feature  of  the  year  has  undoubt- 
edly been  the  continued  progress  of  activated  sludge." 

602  Activated   sludge  experiments  in   England.     ANON.     Munic.  Eng.   and 
Sanit.  Record  66,  ?  Public  Works  49,  567-9.     From  a  report  of  W.  H. 

MAKEPEACE  on  the  Tunstall  sewage  works.  Essentially  the  same  material  as 
covered  by  reference  No.  599.  Air  consumption  was  from  0.624  to  1.108  cu.  ft. 
per  gallon  of  sewage  treated.  Suggestions  for  a  new  plant  are  given. 

603  The  New  Orleans  Meeting,  Am.  Inst.  Chem.  Engrs.     ANON.     Chem.  & 
Met.  Engrg.  23,  1198rl202.     A  brief  review  of  the  papers  presented  in- 
cluding that  on  activated  sludge  by  DR.  E.  BARTOW.     In  the  author's  opinion 
the  greatest  problem  requiring  solution  appears  to  be  an  economical  method  of 
drying  the  sludge.     Experiments  at  Milwaukee  are  referred  to. 

604  Nitrogen  in  sewage.    ANON.    Chem.  Age  (Lond.)  3,  709.    Refers  to  the 
activated  sludge  fertilizer  experiments  at  Harpenden.     According  to  the 

report  of  the  Developments  Commission,  the  total  amount  of  N  contained  in 

100 


A bstract  Bibliography — -1 9W,  , 


the  sewage  of  the  United  Kingdom  is  estimated  at  230,000  tons,  equivalent  to 
1,150,000  tons  of  sulphate  of  ammonia,  most  of  which  is  wasted.  With  the 
general  adoption  of  the  activated  sludge  process  considerable  would  be  added 
to  the  supply  of  organic  manures. 

605  Test  of  Trent  activated  sludge  devices  at  Pasadena.     R.  V.   ORBISON. 
Eng.  News-Record  85,  1286-8.     The  Trent  device  consists  of  revolving 

perforated  arms  of  the  Barker  mill  type,  submerged  in  the  aerating  tanks. 
The  experiments  were  carried  on  for  six  months  and  the  general  conclusion 
reached  was  that  it  was  not  as  satisfactory  as  the  old  aeration  method  through 
filtros  plates,  it  requiring  twice  the  time  and  costing  more  to  operate.  Removal 
of  suspended  solids  and  bacteria,  reduction  of  O  consumed  and  stability,  were 
all  inferior  to  the  old  method.  Plant  consisted  of  four  tanks  designed  to  treat 
50,000  g.  p.  d. 

606  The  conservation  of  nitrogen  with  special  reference  to  activated  sludge. 
G.  J.  FOWLER.  Jour.  Ind.  Inst.  Science.  3,  (Part  VIII)  227-79.     (Decem- 
ber, 1920.)     An  elaborate  and  detailed  account  of  the  sources,  production  and 
consumption  of  N,  with  particular  reference  to  the  possibility  of  recovering 
the  greater  portion   of  the  N  in   sewage.     The  activated   sludge   and   other 
methods  of  sewage  treatment  are  described,  the  following  data  indicating  the 
extent  to  which  first  method  is  considered.    Activated  sludge  as  manure,  giving 
a  summary  of  the  results  obtained  and  conclusions  reached  by  several  workers. 
The  nitrogen  in  activated  sludge,  showing  its  several  combinations  as  revealed 
by  the  experiments  at  the  Frankland  laboratory,  Univ.  of  Manchester,  by  the 
experiments  of  MRS.  MUMFORD,  the  Rothamsted  experiments  and  those  at  the 
Indian  Inst.  of  Science  under  the  author's  direction,  the  latter  pointing  to  a 
fixation  of  atmospheric  N  by  activated  sludge  and  the  suggestion  made  that 
by  the  proper  choice  of  carbohydrate  food,  the  necessary  symbiotic  organisms, 
and  proper  temperature  control,  that  it  may  be  possible  to  build  up  a  special 
activated  sludge  which  will  fix  N  in  quantity  and  at  such  a  rate  that  it  might 
compete  with  commercial  processes.     Paragraphs  are  devoted  to  "The  selec- 
tion of  plants  responsive  to  activated  sludge";  "Effect  of  activated  sludge  on 
special   Indian   crops";   "Condition   of   availability   of  nitrogen   in   activated 
sludge";  "Intensive  cultivation  by  means  of  activated  sludge";  and  "The  dry- 
ing of  activated  sludge  for  transport."    In  the  latter  connection,  electroend os- 
mose is  suggested  as  an  attractive  line  of  attack.     "The  treatment  of  concen- 
trated latrine  sewage  by  activated  sludge"  with  reference  to  conditions  in 
Shanghai,  China,  is  considered  and  several  illustrations  of  present  methods 
of  nightsoil  collection  given.    A  brief  summary  of  the  literature  concludes  the 
article. 


101 


The  Activated  Sludge  Process 
A.SX-:  >:*•.' •  : '•••••  •'•' 

INDEX  OF  LOCATIONS  WITH  SOME  PLANT  DATA. 

Aintree,  Eng. — 1916  on.  Regular  plant  at  National  Filling  Factory.  Popula- 
tion 2,000.  Porous  tile  air  diffusers.  Ref .  505. 

Alhambra,  Calif. — See  Pasadena. 

America.— Ref.  60,  85,  180,  328,  380. 

Argo,  111. — See  Chicago,  Sanitary  District. 

Austin,  Tex. — 1918.  Experimental  plant  at  the  Univ.  of  Texas  in  conjunction 
with  the  city.  Ref.  394. 

Baltimore,  Md. — 1915-6.  Municipal  experimental  plant.  City  sewage.  Aerat- 
ing tank  capacity  200,000  gallons.  Continuous  flow  plan.  Disks  of  FIL- 
TROS,  carborundum  and  perforated  brass  tried  as  air  diffusers.  Ref.  36, 
38,  42,  47,  50,  53,  55,  82,  134,  143,  157,  170,  176,  180,  195,  223,  228,  292. 

Bangalore,  India. — 1917.  Experimental  plant  at  the  Indian  Institute  of  Science, 
for  research  purposes.  Ref.  440,  606. 

Bingley,  Eng. — 1918  on.  Municipal  experimental  plant.  City  sewage.  Treat- 
ment capacity  300,000  g.  p.  d.  on  the  fill  and  draw  plan.  Porous  tile  air 
diffusers.  Ref.  481. 

Blackpole,  Eng. — 1917.  Regular  plant  at  Government  cartridge  factory.  Popu- 
lation 4,000.  Porous  tile  air  diffusers.  Ref.  505. 

Boonton,  N.  J. — 1918.    Plant  proposed  and  plans  approved.    Ref.  313,  315,  403. 

Brampton,  Ont.,  Can. — 1918.  Regular  municipal  plant.  City  sewage.  FIL- 
TROS  air  diffusers.  Ref.  532,  548. 

Brockton,  Mass. — 1915  on.  Municipal  experimental  plant.  City  sewage. 
Aerating  tank  capacity  approx.  4,500'  gallons,  fill  and  draw  plan.  1916, 
continuous  flow  plan.  1917,  plans  preparing  for  a  3  million  g.  p.  d.  plant. 
1918,  postponed  on  account  of  the  war.  Ref.  159,  260,  292,  316,  421. 

Brooklyn,  N.  Y. — 1915  on.  Municipal  experimental  plant.  City  sewage. 
Aerating  tank  capacity  on  fill  and  draw  plan,  16,000  gal.,  on  continuous 
flow  plan,  900  gal.  Air  diffusion  through  perforated  pipes,  carborundum 
and  other  porous  material.  Ref.  7,  31,  61,  88,  103,  104,  109,  115,  130,  143, 
156,  170,  180,  195,  206,  241,  292,  503. 

Burnley,  Eng. — 1920.    Plant  proposed.    Ref.  511. 

Bury,  Eng. — 1920.    Plant  referred  to  in  Ref.  507. 

Canada. — Ref.  54. 

Champaign,  111. — 1915  on.  Municipal  experimental?  plant  in  connection  with 
the  111.  State  Water  Survey.  (See  Urbana.)  Aerating  tank  ca- 
capacity  36,000  gal.  City  sewage.  Continuous  flow  plan.  FILTROS  air 
diffusers.  1920,  a  complete  experimental  plant  of  100,000  g.  p.  d.  proposed. 
Ref.  195,  246,  310,  556. 

Chicago,   111. — Armour   &   Co.,   stockyards.     1915   on.     Private   experimental 
plant.     Packinghouse  wastes.     Aerating  tank  capacity  30,000  gal.     Con- 
tinuous flow  plan.    Perforated  pipe  air  diffusers.    Ref.  86,  90,  128,  173, 
175,  195,  206,  292. 

Chicago,  111. — Sanit.  Dist.     Argo,  111.     1920  on.  Experimental  plant.     Corn 

products    refining   wastes.      Continuous    flow  plan.      Treatment    capacity 

about  50,000  g.  p.  d.     FILTROS  air  diffusers.  Other  methods  being  tried. 
(Private  advice.)     Ref.  541,  589. 

Chicago,  111. — Sanit.  Dist.  Calumet  region.  1920  on.  Regular  plant  under 
construction.  Aerating  capacity  3.5  million  g.  p.  d.  Continuous  flow  plan. 
FILTROS  air  diffusers.  (Private  advice.)  Ref.  541. 

Chicago,  111. — Sanit.  Dist.  DesPlaines  river  plant.  1920  on.  Regular  and 
semi-experimental  plant  under  construction.  Domestic  sewage.  Contin- 
uous flow  plan.  Aerating  capacity  4.5  million  g.  p.  d.  FILTROS  air  dif- 
fusers. Ref.  401,  541,  598. 

102 


Indexes 

Chicago,  111. — Sanit.  Dist.  Griess-Pfleger  testing  station.  1920  on.  Experi- 
mental plant.  Tannery  wastes.  Continuous  flow  plan.  Aerating  capacity 
100,000  g.  p.  d.  FILTROS  air  diffusers.  (Private  advice.)  Ref.  541. 

Chicago,  111. — Sanit.  Dist.  Stockyards.  1915  on.  Experimental  plant.  Mixed 
packinghouse  (75%)  and  domestic  (25%)  sewage.  Aerating  tanks,  four 
of  35,000  gal.  capacity  each  .  Continuous  flow  plan.  Perforated  pipes  and 
FILTROS  air  diffusers  used.  1917,  50  million  g.  p.  d.  plant  recommended, 
FILTROS  air  diffusers  specified.  Ref.  90,  97,  103,  123,  128,  134,  142,  143, 
147,  148,  170,  195,  223,  226,  262,  271,  286,  317,  318,  322,  323,  326,  327, 
337,  345,  365,  366,  380,  394,  408,  476,  478,  482,  484,  501,  513,  533,  541, 
569,  589,  601. 

Chicago,  111.— Sanit.  Dist.  39th  St.  Center.  1916.  Plant  considered.  Ref. 
214. 

Chicago,  111.— Swift  &  Co.,  Morris  &  Co.,  Sulzberger  &  Sons  Co.  1915.  Pri- 
vate experimental  plants.  Packinghouse  wastes.  Ref.  86,  90. 

Cleveland,  O. — 1915  on.  Municipal  experimental  plant.  City  sewage.  De- 
signed to  treat  1  million  g.  p.  d.  Continuous  flow  plan.  FILTROS  air 
diffusers.  Ref.  69,  106,  134,  137,  143,  170,  195,  219,  223,  241,  305,  306, 
325,  356,  357,  359,  369,  390,  394,  430,  431,  576. 

Coleman,  Tex. — 1919.  Regular  plant  and  septic  tanks  treat  entire  sewage 
of  city.  Ref.  493. 

Columbus,  O. — 1920.  Small  experimental  plant.  City  sewage.  FILTROS  air 
diffusers,  (Private  advice). 

Decatur,  111. — 1917.  Municipal  experimental  plant.  City  sewage.  Ref. 
241,  577. 

Decatur,  111. — 1919.  Private  experimental  plant.  Starch  factory  wastes. 
FILTROS  air  diffusers.  (Private  advice). 

East  Walpole,  Mass. — 1916.  Private  experimental  plant.  Paper  mill  wastes. 
(See  Jour.  Ind.  Eng.  Chem.  8,  648.) 

Edmonton,  Alberta,  Can. — 1915  on.  Part  of  regular  municipal  plant.  City 
sewage.  Six  aerating  tanks  of  about  25,000  gal,  capacity  each.  Fill 
and  draw  plan.  Perforated  pipe  diffusers,  Ref.  195,  213,  266. 

El  Dorado,  Kans. — 1920.  Municipal  experimental  plant  under  construction. 
FILTROS  air  diffusers.  (Private  advice). 

England— Ref.  79,  178,  195,  242,  332,  348,  380,  507,  534. 

Escanaba,  Mich. — 1917.  Regular  municipal  plant.  City  sewage.  Aerating 
capacity,  approx.  1  million  g.  p.  d.  Continuous  flow  plan.  FILTROS  air 
diffusers.  Ref.  253. 

Folsom,  Calif. — 1917.  Regular  plant.  Institutional  sewage.  Perforated  pipe 
air  diffusers.  Ref.  358,  567. 

Fort  Worth,  Tex. — 1916-7.  Armour  &  Co.  Private  experimental  plant.  Pack- 
inghouse wastes.  Aerating  capacity  about  86,400  g.  p.  d.  Perforated 
pipes  and  FILTROS  air  diffusers  used.  Ref.  195,  276,  291,  318,  326,  327, 
345,  366,  380,  394,  493. 

Fremont,  Mich. — 1919.  Private  experimental  plant.  Tannery  wastes.  FILTROS 
air  diffusers.  (Private  advice). 

Gainesville,  Tex.— 1919.     Ref.  493. 

Gastonia,  N.  C. — 1920.  Municipal  plant.  City  sewage.  FILTROS  air  diffusers. 
(Private  advice). 

Glasgow,  Scot. — 1920.     Experimental  plant  to  be  recommended.     Ref.  522. 

Grand  Rapids,  Mich. — 1918.  Private  experimental  plant.  Tannery  wastes. 
FILTROS  air  diffusers.  (Private  advice). 

Harpenden,  Eng. — 1918.  Experimental  plant  for  H.  M.  Bd.  of  Agr.  for  pro- 
ducing activated  sludge  for  fertilizer  tests.  Ref.  452,  505,  507,  508, 
553,  604. 

108 


The  Activated  Sludge  Process 

Hermosa  Beach,  Calif. — 1916.  Regular  municipal  plant  proposed.  City  sew- 
age. Treatment  capacity,  400,000  g.  p.  d.  Mechanical  agitation.  Ref. 
179,  208,  567. 

Houston,  Tex. — 1915  on.  Municipal  experimental  plant,  later,  two  regular 
pants.  City  sewage.  Total  treatment  capacity  about  15  million  g.  p.  d. 
Continuous  flow  plan.  FILTROS  air  diffusers.  Ref.  73,  114,  134,  140, 
146,  170,  195,  236,  251,  292,  296,  366,  392,  394,  414,  442,  493,  496,  497, 
510,  513,  536,  589,  597. 

India.— Ref.  184,  281,  348,  440. 

Indianapolis,  Ind. — 1917.  Activated  sludge  process  considered  but  rejected 
as  unsuited  to  local  conditions.  Ref.  346,  347,  400. 

Jersey  City,  N.  J. — See  Boonton,  N.  J. 

Kansas.— Ref.  352. 

Lawrence,  Mass. — 1912  on.  State  experiment  station.  Numerous  studies: 
various  size  tanks.  Perforated  brass  disks  and  FILTROS  air  diffusers  tried. 
Ref.  1,  4,  8,  25,  30,  38,  40,  72,  101,  125,  162,  195,  206,  233,  292,  332,  362, 
409,  446,  519,  520,  524,  529,  534,  549. 

Lima,  Ohio. — 1916.     Activated  sludge  plant  recommended.     Ref.   164. 

Lincoln,  Eng. — 1917.     Experimental  plant  referred  to  in  ref.  366. 

London,  Eng. — 1916  on.  Laboratory  experiments  and  Municipal  experimental 
plant.  Ref.  163,  521,  531,  571,  601. 

Manchester,  Eng. — Bagulay  Sanatorium.  1914.  First  regular  plant  in  Eng- 
land. Fill  and  draw  plan.  Capacity  20,000  g.  p.  d.  Porous  tile  dif- 
fusers. Ref.  91,  111. 

Manchester,  Eng. — Davyhulme  works.  1913  on.  Municipal  experimental  plant. 
City  sewage.  Numerous  experiments.  1918-9.  1  million  g.  p.  d.  plant 
under  construction.  Continuous  flow  plan.  Ref.  8,  26,  38,  120,  134,  372, 
397,  449,  452,  485,  499,  505,  508,  525,  594. 

Manchester,  Eng. — Withington  works.  1913  on.  Municipal  experimental 
plant.  City  sewage.  Numerous  experiments.  1918.  Continuous  flow 
tanks  treating  up  to  375,000  g.  p.  d.  Ref.  199,  244,  366,  379,  381,  397, 
417,  420,  425,  449,  485,  499,  505,  507,  514,  525,  527. 

Manchester,  Eng.— Works  not  stated.  Ref.  9,  12,  24,  35,  36,  40,  64,  71,  72, 
103,  106,  125,  152,  162,  198,  224,  232,  234,  292,  296,  373,  442,  479,  519, 
524,  529,  600. 

Matawan,  N.  J. — 1916.     Plans  for  plant  approved.     Ref.  171. 

Maynard,  Mass. — 1916.  Private  experimental  plant.  Woolen  mill  wastes. 
(See  Jour.  Ind.  Eng.  Chem.  8,  648.) 

Milwaukee,  Wis. — 1914  on.  Municipal  experimental  plant.  City  sewage, 
numerous  experiments  with  aerating  tanks  of  various  sizes  on  both 
fill  and  draw  and  continuous  flow  plans.  Perforated  pipes,  wood  blocks 
and  FILTROS  air  diffusers  tried.  1920.  85  million  g.  p.  d.  regular  plant 
under  construction,  FILTROS  air  diffusers  specified.  Ref.  38,  44,  58,  66, 
70,  72,  75,  76,  81,  87,  88,  89,  91,  100,  103,  106,  112,  116,  117,  121,  122, 
125,  126,  134,  136,  138,  141,  143,  145,  147,  150,  151,  153,  170,  180,  188, 
191,  193,  195,  197,  205,  206,  207,  223,  227,  229,  232,  234,  240,  245,  280, 
288,  292,  296,  328,  330,  332,  333,  353,  356,  364,  365,  366,  370,  377,  389, 
394,  398,  408,  417,  442,  453,  464,  471,  491,  500,  512,  513,  526,  550,  554, 
555,  584,  589,  590,  601,  603. 

Milwaukee,  Wis. — 1915.  Private  experimental  plant.  Tannery  wastes.  FILTROS 
air  diffusers.  (Private  advice).  Ref.  289. 

Moreton,  Eng. — (Near  Worcester).  191  ?  Regular  plant  for  Admiralty  Air- 
ship Station.  Population,  400.  Porous  tile  diffusers.  Ref.  301,  452,  505. 

Moscow,  Russia. — 1917.  Experimental  plant.  Fill  and  draw  plan.  Capacity 
135,000  g.  p.  d.  Perforated  pipe  diffusers.  (Noted  in  K.  W.  &  P.  Book. 
Ref.  506). 

104 


Indexes 

Mt.   Vernon,   N.   Y. — 1919.      Experimental    plant,   privately   conducted.      City 

sewage.     Treatment  capacity,  45,000  g.  p.  d.     Mechanical  agitation  and 

FILTROS  air  diffusers.     Ref.  477,  579,  581. 
New   Britain,    Conn. — 1920.      Municipal    experimental   plant.        City   sewage. 

FILTROS  air  diffusers.     (Private  advice). 
New  Haven,  Conn. — 1917  on.     Experiment  station.     City  sewage.     Treatment 

capacity,  17,000  g.  p.  d.    Continuous  flow  plan.    FILTROS  air  diffusers  used. 

Ref.  329,  338,  354,  426,  432,  448,  462,  592. 
North  Toronto,  Can.— Ref.  248,  272. 
Norwood,    Mass. — 1916.      Private    experimental    plant.      Tannery    and    wool 

scouring  wastes.    Aerating  tank,  1,000  gal.  capacity.    Fill  and  draw  plan. 

FILTROS  air  diffusers.     Ref.  203,  292. 

Paris,  France. — 1917.     Laboratory  experiments.     Ref.  340. 
Paris,  Texas. — 1916.     Regular   municipal   plant.     City   sewage.     FILTROS  air 

diffusers  used.     Ref.  493. 
Pasadena,   Calif. — 1916  on.     Experimental  municipal  plant.     City  sewage  of 

South  Pasadena  and  Alhambra  included.     Treatment  capacity  50,000  g. 

p.  d.     FILTROS  air  diffusers.     1919-20.     Trent  agitating  devices  tried.   Ref. 

132,  210,  250,  257,  331,  349,  374,  572,  605. 

Peterboro,  Ont.,  Can. — 1920.     Activated  sludge  plant  considered.     Ref.  585. 
Pittsfield,    Mass. — 1920.      Private    experimental    plant.         Industrial    wastes. 

FILTROS  air  diffusers.     (Private  advice). 
Port  Colborne,  Ont.,  Can. — 1917.     Private  regular  plant.     Metallurgical  and 

domestic  wastes.     FILTROS  air  diffusers.     (Private  advice). 
Port  Colborne,  Ont.,  Can. — 1920.     Regular  municipal  plant  considered.     Ref. 

575. 
Providence,  R.  I. — 1917.    Municipal  experimental  plant.    City  sewage.   FILTROS 

air  diffusers.     (Private  advice). 

Quanah,  Texas. — 1918.     Regular  municipal  plant.     Ref.  493. 
Reading,  Eng. — 1919.     Activated  sludge  process  adopted  to  treat  entire  city 

sewage.     Ref.  461,  472,  508,  557,  583,  586,  591,  596. 
Regina,   Sask.,   Can. — 1915.      Municipal    experimental   plant.        City   sewage. 

Aerating  tanks,  two  of  577.8   Imp.  gallons   each.     Fill   and  draw  plan. 

Air  diffused  through  perforated  pipes  covered  with  canvas.     Ref.  38,  54, 

134,  195,  230,  249. 
Sakchi,    India. — 191?      Plant    considered   to    care    for   future    population    of 

150,000.     Ref.  281,  440. 

Salford,  Eng. — 1914  on.     Municipal  experimental  plant.     City  sewage.    Treat- 
ment  capacity,   75,000  gal.   in   21   hours   on   fill   and   draw  plan;    60,000 

g.  p.   d.  on  continuous  flow  plan.     Perforated  pipe  air  diffusers.     1919. 

Adoption   recommended  for  regular  plant.     Ref.  22,  24,  26,  29,  36,  38, 

62,  64,  93,  95,  102,  106,  133,  134,  232,  240,  244,  292,  296,  366,  372,  417,  475. 
San  Angelo,  Tex. — 1919.    Regular  municipal  plant.     City  sewage.    Treatment 

capacity,  400,000  g.  p.  d.    Perforated  pipe  air  diffusers.    Ref.  493,  518. 
San  Marcos,  Tex. — 1916.     Regular  municipal  plant;  beieved  to  be  the  first  in 

the  U.   S.  treating  the  entire   sewage  of   a   city.     Treatment   capacity, 

150,000  g.  p.  d.    FILTROS  air  diffusers.     Ref.  195,  197,  252,  259,  394,  493. 
Sarisbury  Court,  Eng. — (Near  Southampton).     1918.    Hospital  installation  for 

200  patients  and  staff.     Porous  tile  air  diffusers.     Ref.  452,  486,  505. 
Shanghai,  China. — 1919.    Experimental  municipal  plant  recommended.  FILTROS 

air  diffusers.     Ref.  436,  474,  578,  606. 

Sheffield,  Eng. — 1915  on.     Experimental  municipal  plant.     City  sewage.     Nu- 
merous   experiments.      1919:    aerating   tanks    treating    110,000    g.    p.    d. 

using  mechanical  agitation.     1920:  1  million  g.  p.  d.  plant  building.     Ref. 

167,  168,  215,  232,  328,  366,  458,  468,  469,  479,  481,  502,  511,  514,  529, 

553,  578. 

105 


The  Activated  Sludge  Process 

Sherman,  Tex. — 1918.  Regular  municipal  plant.  City  sewage.  FILTROS  air 
diffusers.  Ref.  493. 

Shieldhall,  Scot. — See  Glasgow. 

South  Pasadena,  Calif. — See  Pasadena. 

St.  Albans,  Eng. — 1918.  Experimental  municipal  plant.  City  sewage.  Treat- 
ment capacity  30,000  g.  p.  d.  Continuous  flow  plan.  Porous  tile  diffusers. 
Ref.  422,  442,  452. 

Stamford,  Eng. — 1915  on.  Experimental  municipal  plant.  City  sewage. 
Treating  100,000  g.  p.  d.  Porous  tile  air  diffusers.  Ref.  91,  111,  134, 
232,  240,  296,  366,  381,  417,  505. 

Sydney,  Australia. — 1916  on.  Experimental  municipal  plant.  Aerating  tanks, 
500  and  10,000  gal.  capacity.  Fill  and  draw  plan.  Perforated  pipes 
covered  with  broken  stone  for  air  diffusion.  1919-20.  Treating  900,000 
g.  p.  d.  Ref.  320,  568,  588. 

Syracuse,  N.  Y. — 1917  on.  Municipal  experimental  plant.  City  sewage. 
Aerating  tank  approximately  3,000  gal.  capacity.  Continuous  flow  plan. 
Perforated  pipe  air  diffusers.  Ref.  363,  378,  484. 

Texas.— Ref.  447,  457,  465,  493,  504. 

Toronto,  Can. — 1920.  Small  experimental  plant.  FILTROS  air  diffusers.  (Pri- 
vate advice). 

Tunstall,  Eng. — 1918.  Municipal  experimental  plant.  City  sewage.  Treat- 
ing 300,000  g.  p.  d.  on  continuous  flow  plan.  Porous  tile  air  diffusers. 
Ref.  452,  489,  505,  507,  562,  593,  595,  599,  602. 

United  States.— Ref.  36,  66,  178,  348,  420. 

Urbana,  111. — 1914  on.  Experiment  station  111.  State  Water  Survey  at  the 
Univ.  of  111.  Numerous  investigations.  Believed  to  be  the  first  ex- 
clusive activated  sludge  plant  in  the  U.  S.  First  to  use  FILTROS  air 
diffusers.  Ref.  35,  38,  43,  72,  88,  113,  116,  121,  135,  170,  195,  210,  232, 
292,  296,  302,  310,  394,  408,  556,  589. 

Wakefield,  Eng. — 1915  on.  Municpial  experimental  plant.  City  sewage.  Ca- 
pacity of  aerating  tank  approximately  13,500  gal.  on  fill  and  draw  plan. 
Porous  tile  air  diffusers.  Ref.  20,  38,  63. 

Wimbledon,  Eng. — 1916.  Aeration  experiments  contemplated,  using  atomizers. 
Ref.  107,  108. 

Woodstock,  Ont.,  Can. — 1920.  Regular  municipal  plant  building.  FILTROS 
air  diffusers.  (Private  advice). 

Worcester,  Eng. — 1915  on.  Municipal  experimental  plant.  City  sewage.  Nu- 
merous experiments.  1916:  treating  750,000  g.  p.  d.  on  continuous  flow 
plan.  Porous  tile  air  diffusers.  Ref.  91,  102,  111,  134,  172,  174,  232,  240, 
242,  247,  278,  279,  282,  283,  284,  293,  295,  296,  298,  299,  300,  360,  366, 
379,  397,  415,  417,  442,  452,  463,  470,  505,  601. 

Worcester,  Mass. — 1917-8.  Municipal  experimental  plant.  City  sewage. 
Treatment  capacity,  100,000  g.  p.  d.  Continuous  flow  plan.  FILTROS 
air  diffusers.  Ref.  223,  258,  260,  351,  437,  487,  540. 

York  Township,  Ont.,  Can. — 1919.  Activated  sludge  process  considered. 
Ref.  498. 


106 


Indexes 


INDEX  OF  NAMES 


Ref. 
Activated  Sludge  Lt'd.  505-516-551-552 

Adams,  G.  O. 6-30-125 

Adams,  S.  H. 272-330-473-529 

Allen,  K.   355-365-382-408 

Allen,  W.  J. 587 

Allin,  T.  D. 182-210-223 

Alvord,  J.  W.   212-269 

Ames,  R. 127-194-255-285-466 

Ames-Crosta  Sanit.  Eng.  Co. 516 

Adern,    E.    9-19-22-23-24-25-26-29 

-32-36-38-40-52-64-71-103 
-106-120-124-125-134-150-162 
-244-264-265-292-296-307-328 
-339-379-425-442-507-527-534 

Armour  &  Co. 86-90-128-173 

195-383-384-385 

Baker,  W.  N. 60-99 

Ball,  C.  H 167-600 

Barber,  F.   498 

Barford,  J.  B. 95 

Bartow,  E. 35-38-41-43-45-83-84 

-85-88-103-105-113-118-120 
-121-125-134-135-158-169-170 
-183-186-211-241-246-261-290 
-292-302-303-310-312-319-321 
-361-367-406-444-556-589-603 

Barwise,  S.   95-166-174-297 

Beckett,  W.  M. 16 

Black,  Gen.  Wm.   M 125-130-292 

Bleazard,  A.  R. 133 

Bottomly,  H. 481 

Boulton,  J. 507 

Bowes,   ?.     ?.     139 

Bowes,   A.   133 

Brenchley,  W.  E. 538 

Brosius,  A.  M. 179-208-438 

Brown,  R. 65 

Buckley,  Wm 410-413 

Butcher,  W.  L. 258 

Caink,  T_. 149-247-279-282-283 

-294-295-298-299-300-350-379-470 

Calvert,  H.  T. 484 

Cambier,  R.   528-563-570 

Carpenter,  Geo.  A.  231 

Carpenter,  W.  T 88-109-200-230 

Chase,  E.  S 544 

Chemical  Process  Co. 411-412 

Clark,    H.    W.    1-4-6-30-38-40-101 

-125-162-169-183-233-292 
-362-434-446-529-534-537 

Clifford,  Wm. 274-275-379 

-381-449-537-565 

Coombs,  J.  A.   379-551-552 

Cooper,  C.  H. 37-65-107-108 

Copeland,  W.  R. 100-131-138 

-141-187-188-189-190-191-227 

-230-267-377-424-453-491-500 

Cotterell,  A.  P.  I. 134-553 


Ref. 

Coulter,  W.  S. 53-273 

Courmont,  P.   509-539-547 

Cox,  J.  W 439 

Crawford,  F.  N. 158-335 

Crocker,  H.  S. 316 

Cronin,  A.   320 

Crump,  E.  H. 65 

Dallyn,  F.  A. 169-183-365-443 

Dickson,  A. 189-206-328 

Dienert,  F. 340-530-535-545 

Dorr  Co. 324-345-377-477-491 

-555-579-580-581-598 

Dorr,  E.  S.  _459 

Duckworth,  W.  H. 21-22-24-29-32 

-38-52-93-95-96-133-292-299 

Eade,  J. 422 

Eagles,  R.  H. 579-581 

Eddy,  H.  P. 136-155-160-203-204 

-212-217-269-270-431 

Ehlers,  V.  M. 447-504 

Ellis,  J.  R. 230-249 

Elrod,  H.  E. 252 

Evans,  H.  P. 352 

Fales,  A.  L. 160-311 

Farmer,  J.  E. 600 

Fieldhouse,  J.  553 

Fogg,  Tom 133 

Folwell,  A.  P. 230-234 

Fort,  E.  J. 61-156 

Fothergill,  H.  455 

Fowler,  G.  J. 2-8-9-24-29-32-38-40 

-44-51-52-91-103-119-120-121 
-124-125-129-134-150-162-184 
-206-243-281-292-309-332-376 
-436-454-467-524-529-534-606 
Frank,  L.  C. 36-47-48-50 

-110-129-170-176-515 

Fugate,  G.  L.  497-510-536 

Fuller,  G.  W. 89-164-189-212-230 

-269-346-347-365-400-420-460 

Fuller,  W.  B.  104 

Gage,  S.  DeM. 1-4-38-125 

Gascoigne,  G.  B._ .219-277-356-389-576 

Gault,  M 351-437-487 

Gaunt,  P. 9-95-124-265-379 

Gillespie,  P. 52 

Girault,  ?.  ? 535 

Goddard,  C.  W. 504 

Godfrey,  C.  H. 474-578 

Gononian,  Y.  H. 235 

Gooseman,  A.  T. 65 

Griffiths  &  Hartley 181-314-396 

Grossmann,  J.  9-24 

Halliwell,  ?.  ?. 124 

Hammond,  Geo.  T._  .7-115-130-143-144 

-169-170-180-183-192 

-195-206-266-268-503 
Harding,  M.  D 173-175 


107 


The  Activated  Sludge  Process 


INDEX  OF  NAMES  (Cont.) 


Ref. 

Hartley  &  Hartley 450-483 

Hatfield,  W.  D. 84-118-406-444 

Hatton,  T.  C. 58-70-75-88 

-100-103-106-110-117-120^121 
-122-125-126-129-131-138-151 
-153-154-169-170-180-183-207 
-227-229-230-239-245-246-280 
-292-324-332-333-348-353-356 
-370-377-389-393-416-451-453 
-464-500-512-526-554-555-589 

Haworth,  J.   167-168-174 

-215-458-514-529 

Hendrick,  C.  W. 47-50-157-170 

Hering,  R 121 

Hewes,  C.  E. __132 

Hicks,  P.  T 241 

Holmes,  G.  D. 153-378 

Hommon,  H.  B. 289-513 

Horowitz,  M.  P. 200 

Horton,  Theo. 574 

Hoseason,  J.  H. 265 

Hoskins,  J.  K 513 

Houston,  A.  C. 502 

Jackson,  L.  E. 352 

Johnson,  G.  A. 171-315 

Jones,  E.  R 407-566 

Jones,  W. 3-5-10-11-15 

-17-18-28-33-165-222-256 
-308-341-342-343-344-402 
-404-418-419-428-435-561 

Jones,  W.  M. 133 

Jones  &  Attwood,  L'td. 3-5-10-11 

-15-17-18-28-33-91-110-111 
-120-129-165-172-222-243-256 
-274-275-278-282-284-293-308 
-381-404-418-419-452-516-565 

Radish,  V 289 

Kamm,  W.  F. 336 

Kershaw,  G.  B 31-134-365-391-441 

Kershaw,  J.  H. 167-507 

Kinnicutt,  Winslow  &  Pratt. _. 506-524 

Knowles,  M. 445 

Lacey,  G.  W. 379 

Lamb,  J. 95-507 

Lanphear,  R.  S. 540 

Launey,  M. 545 

Lederer,  A.  J 123-142-148 

Lester,  J.  H 24 

Lockett,  W.  T 9-19-22-23-25-32-36 

-38-40-52-64-71-103-106-124 
-125-134-150-162-263-292-534 

Lockett  &  Herring-Shaw 304 

Long,  E. 74 

MacMillan,  J.  _  __132 

Makepeace,  W.  H. 95-263-507-562 

-594-595-599-602 

Martin,  A.  J. 429-433-494-495 

-507-553-558-601 


Ref. 

Martin,  E.  B 62-65-92 

McFarland,  D.  F. 368 

McGowan,  Dr.  G. 134-546-553-601 

McKay,  G.  P. 405-406-451 

McKenn,  R.  J. 133 

McVea,  J.  C. 497-589-597 

Melling,  S.  E. 9-24-32-38-64 

-265-292-372-379-388 

Metcalf  &  Eddy  72 

Mickle,  F.  L. 367 

Miln,  G.  P. 379 

Mohlman,  F.  W. 43-45-83 

-211-246-261-292-329-334 
-354-426-432-448-459-484 

Moor,  W»  C. 383 

Moore,  George 411-412 

Morris  &  Co. 90 

Mottram,  G.  W. 34-39-177 

Mulloy,  G.  B. 384 

Mumford,  E.  M. 2-38 

Mumford,  G. 51-152-454-490 

Nasmith,  G.  G.—216-405-406-451-492 

Naylor,  G.  W.  &  J.  F 13-14-20 

-27-56-57-221 

Naylor,  W. 19 

Noble,  G.  L. 161-170-173-175 

-230-291-292-385 

Nordell,  C.  H._ .78-201-225-230-288-427 
Orbison,  R.  V. 132-182-210-223 

-257-331-349-605 

O'Shaugnessy,  F.  R 9-232 

Pacific  Flush  Tank  Co 439 

Parsons,  F.  W. 584 

Pearse,  L 123-170-246-262-271-286 

-317-322-323-326-327-337-365 

-371-478-482-533-569-589-598 

Phelps,  E.  B.__125-130-169-183-230-292 

Phelps,  Geo. 248 

Potter,  Alex. 230 

Pratt,  R.  W.—69-137-170-219-369-506 

Reid,  G.  G. 532 

Rein,  L.  E. 439 

Requardt,  G.  J. 55-228-237 

Rhynus,  C.  P. 515 

Rice,  J.  M 445 

Richards,  E.  H. 538 

Richardson,  W.  D 262-271-286 

-317-322-323-365 

Rideal,  S. 95-218-240-366-379 

Rochaix,  A. 509-539-547 

Roechling,  H.  A. 134 

Rolants,  E. 488 

Rudnick,  P.  __  161-173-175-246-292-406 

Russel,  R.  186 

Sands,  E.  E. 73-114-170-236-414 

Schnellbach,  J.  F 211-246-261 

Scott-Moncrieff,  W.  D 95 

Scouller,  W.  D. 379 


108 


Indexes 


INDEX  OF  NAMES  (Cont.) 


Ref. 
Silcock,  E.  J.  _.  __65 

Smail,  J.  W. 588 

Smith,  C 134 

Stein,  M.  F. 517 

Stevenson,  W.  L. 67-230 

Stott,  O. 407-566 

Streeter,  H.  W. 513 

Sulzberger  &  Sons  Co. 86-90 

Swift  &  Co. 90 

Tarbett,  R.  E. 513 

Taylor,  G.  M. 557-583 

Thompson,  J.  T. 9 

Thompson,  W 24-124-265 

Traxler,  H. 125 

Tyler,  R.  G 394 

Upton,  R.  G. 465 

Veatch,  F.  M. 352 

Wagenhals,  H.  H. 513 


Ref. 

Wakeford,  J.  P 24-32-38-49 

-62-63-65-481 

Wandenbulke,  F.  545 

Watson,  J.  D. 62-65-479 

Wells,  R 484 

Weston,  R.  S 159-365-459-542-592 

Whyte,  L. 455 

Wilcox,  J.  E. 417 

Wilcox,  W.  F. 135 

Wilkinson,  O.  J. 80-82 

Williford,  C.  L.  251 

Wilson,  H.  M 59-150-162-484-534 

Winslow,  C.  E.  A 365-426-432 

-448-459-506 
Wynne-Roberts,  R.  O 38-52-54 

-145-498-575 

Young,  M. 372-379-388 

Zimmele,  G.  B 259-276-291 


Oct.  11.  Brit. 


INDEX  OF  PATENTS 

1913.                          Ref.  Ref. 

22,952  (J   &   A) 3     Dec.  19.  U.S.  1,208,821  (Nordell)   ___225 


Jan.  10. 
Apr.  11. 
Apr.  11. 
Sep.  28. 
Oct.  6. 
Nov.  4. 
Nov.  4. 
Nov.  19. 
Nov.  19. 
Nov.  27. 
Dec.  21. 
Dec.  24. 


Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 
Brit. 


Jan.  23. 
Feb.  16. 
Mar.  10. 
Mar.  18. 
May  11. 
June  7. 
June  7. 
July  9. 
Oct.  19. 
Dec.  14. 


Feb.  25. 
Apr.  10. 
May  20. 
July  11. 
Aug.  15. 
Aug.  26. 
Oct.  13. 
Dec.  7. 
Dec.  9. 


Brit. 

Brit. 

Brit. 

Brit. 

U.  S. 

Brit. 

Brit. 

Brit. 

Brit. 

Brit. 


1914. 
729 
19,915 
19,916 
20,259 
20,579 
21,976 
21,985 
22,736 
22,737 
23,146 
24,386 
24,630 

1915. 
1,141 
2,421 
3,831 
4,240 
1,139,024 
8,397 
9,870 


1917. 


(J   &   A). 
(J   &   A). 
(J   &   A). 
(Naylor) 
(Naylor) 
(J  &  A). 
(Beckett) 
(J   &  A). 
(J  &  A). 
(Naylor) 
(Naylor) 
(J   &  A). 


._  5 
._  10 
._  11 
._  13 
._  14 
._  15 
._  16 
._  17 
._  18 
._  20 
_  27 
_  28 


14,733 
17,463 


1916. 

Brit.  104,361 
Britap.  5,215 
Brit.  105,654 
Brit.  104,187 
U.S.  1,195,067 
Brit.  ap.  12,084 
Brit.  110,197 
Brit.  111,548 
Brit.  111,720 


(J  &  A) 33 

(Mottram)  _  34 
(Cooper)  ___  37 
(Mottram)  __  39 
(Frank)  .48,110 
(Fowler)  ___  51 
(Naylor)  ___  56 
(Naylor)  ___  57 

(Long) 74 

(Martin)    ___  92 


(Ames)    127 

(Bowes) 139 

(Caink)    149 

(Jones)    165 

(Mottram)  —177 
(Griffith)    ___181 

(Ames)    194 

(Naylor)    —221 
(J  &  A) 222 


Feb.  24. 
Feb.  26. 
May  17. 
May  24. 
June  19. 
July  7. 
Aug.  11. 
Aug.  11. 
Aug.24. 
Aug.  27. 
Sep.  18. 
Nov.  20. 
Nov.  20. 
Nov.  20. 
Nov.  20. 

Jan.  29. 
Jan.  29. 
Jan.  29. 
Mar.  18. 
Apr.  16. 
Apr.  27. 
May  14. 
July  2. 
July  9. 
July  9. 
July  24. 
Aug.  17. 
Aug.  17. 
Oct.  15. 
Oct.  22. 
Nov.  26. 
Dec.  3. 
Dec.  3. 


107,937 
113,333 
115,872 
117,472 
115,933 
116,580 


Brit. 

Brit. 

Brit. 

Brit. 

Brit. 

Brit. 

Brt.  ap.  11,561 

Brt.  ap.  11,562 

Brit.       122,428 

Dan.        22,389 

Brt.  ap.  13,374 

U.S.   1,247,540 

U.S.   1,247,541 

U.S.  1,247,542 

U.S.   1,247,543 

1918. 


U.S. 
U.S. 
U.S. 
Brit. 
Can. 
Brit. 
Brit. 
U.S. 
U.S. 
U.S. 
Brit. 
Brit. 
Brit. 
U.S. 
U.S. 
U.S. 
U.S. 
U.S. 


1,254,833 

1,254,836 

1,254,841 

ap.  4,276 

183,586 

132,826 

133,722 

1,271,425 

1,271,925 

1,271,926 

130,146 

131,158 

132,581 

1,281,816 

1,282,587 

1,286,017 

1,286,520 

1,286,775 


(Ames)    

(J  &  A)___. 
(Clifford)  _. 
(Clifford)  __. 

(Ames)    

(Caink)  ___. 
(H-S  &  L)_ 
(H-S  &  L)_ 

(Jones)    

(Fowler)  __. 
(Griffith)  __. 

(Jones)    

(Jones)    

(Jones)    

(Jones)    

(Moor)   _ 
(Mulloy) 
(Noble) 
(Griffith)    __. 

(Jones)    

(Jones)    

(Stott  &  J)_. 
(Buckley)  _. 

(Moore)   

(Moore)   

(Buckley)    _. 

(Jones)    

(Jones)    

(Nordell)  __. 

(Jones)    

(Jones)    

(Brosius)  __. 
(Rein,  et  aL). 


.255 
.256 
.274 
.275 
.285 
.294 
.304 
.304 


.314 
.341 
.342 
.343 
.344 

.383 

.384 
.385 
.396 
.402 
.404 
.407 
.410 
.411 
.412 
.413 
.418 
.419 
.427 
.428 
.435 


109 


The  Activated  Sludge  Process 


INDEX  OF  PATENTS  (Cont.) 


1919.  Ref. 

Jan.  22.  Brit.ap.  1,604  (Hartley)  —450 
Feb.  11.  U.  S.  1,294,080  (Fowler)  ___454 
Feb.  28.  Brit.  104,189  (Whyte  &  F.)455 

Apr.  28.  Brit.      143,369  (Ames)    466 

Apr.  29  Can.  189,921  (Fowler)  ___467 
Aug.  1.  Brit.  145,291  (Adams)  ___473 
Nov.  5.  Britap.  27,205  (Hartley)  —483 


Ref. 

Dec.  6.  Brit.ap.    30,579  (Mumford)    _490 

1920. 

May  13.  Brit.  ap.  13,202  (A.  S.  Lt'd)._551 
May  13.  Brit.  ap.  13,203  (A.  S.  Lt'd)__552 

May  25.  U.  S.  1,341,561  (Jones)    561 

June  15.  U.  S.  1,343,764  (Clifford)  ___565 
June  15.  U.  S.  1,343,797  (Stott  &  J.)__566 


INDEX  OF  PERIODICALS. 

(Though  more  than  50  regularly  issued  periodicals  are  mentioned  in  this 
bibliography,  only  those  most  frequently  referred  to  and  which  contain  substantially 
complete  articles  are  here  indexed.  Indexes  of  abstract  journals,  annual  reports, 
pamphlets,  etc.,  are  omitted.) 


THE  AMERICAN  CITY. 

Volume  14,  1916.  Ref. 

Jan.     pp.     78-81  (Fuller) 103 

Mar.    pp.  282-5      (Bartow,  et  al.)___  84 

Volume  16,  1917. 
June    pp.  804-7      (Phelps)   248 

Volume  18,  1918. 

Jan.     pp.       1-4      (Anon.) 370 

Feby.  pp.  114-9      (Anon.) 370 

Mar.    pp.  199-208  (Anon.) 370 

Volume  20,  1919. 

June    pp.  467-9      (Winslow,  et  al.)__459 
Volume  22.  1920. 

Feby.  pp.  147-8      (Anon.) 518 

May    pp.  485-9      (Chase)    544 

AMERICAN  JOURNAL   OF 
PUBLIC  HEALTH 

Volume  6,  1916.  Ref. 

Nov.  pp.  1218-23    (Carpenter,  et  al.)_200 

Volume  7,  1917. 

Aug.      p.  679         (Bartow,  et  al.)___211 
Oct.       p.  847         (Anon.)    202 

Volume  8,  1918. 

Jan.    pp.    47-54    (Pearse)   371 

Jan.     pp.     55-7      (Pratt)    369 

Volume  10,  1920. 
May    pp.  405-7      (Weston)    542 

CANADIAN   ENGINEER 

Volume  28,  1915.  Ref. 

Mar.  11,  pp.  335-6    (Wynne-Roberts)  38 

June  24,  pp.  697-9   (Wynne-Roberts)  52 
Volume  29,  1915. 

July  1,  p.   112   (Wynne-Roberts) 54 

Aug.  5,  p.  239  (Edit.) 64 

Aug.  12,  pp.  249-51  (Wakeford) 49 

Sep.  30,  p.  429  (Wakeford) 63 


CANADIAN  ENGINEER  (Contd.) 
Volume  29,  1915   (Cont.)        Ref. 

Oct.  21,  p.  503  (Sands) 73 

Oct.  28,  pp.  517-9  (Hatton) 75 

Nov.  4,  pp.  549-50   (Hatton) 75 

Volume  30,  1916. 

Feb.  10,  pp.  227-8  (Fowler) 121 

Apr.  27,  pp.  473-6  ( Wynne-Roberts  )__145 
May  25,  pp.  561-5  ( Wynne-Roberts  )__145 

May  25,  p.  581  (Edit.) 150 

June  1,  pp.  590-2   (Hatton) 151 

Volume  31,  1916. 

Aug.  31,  pp.  167-9  (Haworth) 168 

Oct.  19,  pp.  305-11   (Hammond) 195 

Oct.  26,  p.  340  (Copeland) 188 

Nov.  2,  pp.  353-5  (Eddy)____ 203 

Dec.  7,  p.  475  (Edit.) 220 

Dec.  14,  pp.  489-90  (Anon.) 224 

Volume  32,  1917. 

Feb.  1,  p.  82  (Rideal) 218 

Feb.  8,  pp.  117-21  (Phelps) 248 

Feb.  8,  pp.  124-6  (Ellis) 249 

Feb.  15,  p.  157  (Rideal) 218 

Mar.  8,  pp.  214-6  (Anon.) 254 

Mar.  29,  p.  265  (Anon.) 266 

June  14,  pp.  491-4   (Hatton) 280 

Volume  33,  1917. 

July  12,  pp.  30,  38-40  (Anon.) 295 

Sept.  13,  p.  230  (Fales) 311 

Oct.  18,  pp.  339-41  (Bartow) 312 

Oct.  25,  pp.  358-9  (Pearse) 326 

Dec.  6,  pp.  473-4  (Allen) 355 

Volume  34,  1918. 

Feb.  14,  p.  144   (Anon.) 386 

Mar.  21,  pp.  243-5  (Kershaw) 391 

Apr.  4,  p.  294  (Anon.) 397 

May  2,  pp.  377-82  (Nasmith,  et  al.)_405 

Volume  35,  1918. 

Sep.  5,  pp.  224-5  (Wilcox) 417 

Oct.  3,  pp.  302,  315-7  (Copeland) 424 


110 


Indexes 


INDEX  OF  PERIODICALS  (Cont.) 


CANADIAN  ENGINEER  (Cont.) 

Volume  36,  1919.  Ref. 

Feb.  13,  pp.  222-3  (Anon.) 449 

Apr.  24,  p.  404  (Anon.) 462 

May  15,  pp.  455-60  (Dorr  et  al.) 459 

Volume  37,  1919. 

July  3,  p.  46  (News  item) 471 

Oct.  30,  pp.  420-2,  427-9   (Watson)__479 

Dec.  11,  pp.  519-22   (Nasmith) 492 

Dec.  25,  pp.  559-60  (Anon.) 498 

Dec.  25,  pp.  563-6  (Wells) 484 

Volume  38,  1920. 

Feb.  26,  pp.  245-7  (Anon.) 499 

Mar.  18,  pp.  314-5   (Adams) 529 

Apr.  8,  pp.  367-8  (Fuller) 460 

June  3,  p.  522  (Anon.) 559 

Volume  39,  1920. 

Aug.  19,  p.  269  (Anon.) 575 

Oct.  7,  p.  410  (News  item) 585 

Dec.  23,  pp.  627-8  (Anon.) 586 

COMPTES  RENDUS   (Acd.  Sci.) 

Volume  165,  1917.  Ref. 

Nov.   ?,  pp.  1116-7  (Dienert) 340 

Volume  170,  1920. 

Jan.  5,  pp.  75-8  (Courmont) 509 

Mar.  15,  pp.  681-4   (Cambier) 528 

Mar.  22,  pp.  762-3  (Dienert) ____530 

Apr.  12,  pp.  899-901  (Dienert) 535 

Apr.  19,  pp.  967-70  (Courmont) 539 

May  3,  pp.  1089-92  (Dienert) 545 

May  17,  pp.  1134-5  (Courmont) 547 

June  7,  pp.  1417-9  (Cambier) 563 

Volume  171,  1920. 
July  5,  pp.  57-60  (Cambier) 570 

CONTRACT  RECORD 

Volume  29,  1915.  Ref. 

June  23,  pp.  647-9  (Wynne-Roberts)—  38 

Volume   30,   1916. 

Apr.  19,  pp.  382-5  (Hatton) 117 

Aug.  9,  pp.  788-90  (Anon.) 175 

Oct.  4,  pp.  959-62   (Haworth) 168 

Nov.  8,  pp.  1066-8  (Anon.) 205 

Nov.  8,  p.  1074  (Anon.) 206 

Volume   33,   1919. 
Dec.  10,  pp.  1137-40  (Nasmith) 492 

Volume   34,   1920. 
Mar.  31,  pp.  292-7  (Reid) 532 

THE  ENGINEER 

Volume  117,   1914.              Ref. 
Mar.  6,  p.  272  (Fowler) 8 

Volume  119,  1915. 
Jan,  8,  p.  32   (Anon.) 32 


THE  ENGINEER  (Cont.) 

Volume  120,  1915.              Ref. 
Dec.  31,  pp.  620-1   (Duckworth) 93 

Volume  121,  1916. 

Jan.  14,  pp.  30-1  (Anon.) 106 

Jan.  21,  pp.  58-9  (Hatton) 70,  75 

Volume   122,  1916. 
Aug.  25,  p.   170   (Anon.) 180 

Volume  123,  1917. 

Jan,   12,  pp.  32-3    (Anon.) 240 

Apr.  13,  pp.  337-8  (Phelps) 248 

Apr.  27,  p.  375   (Adams) 272 

Volume  124,  1917. 

Aug.  3,  p.  94  (Ardern) 296 

Dec.  28,  p.  561  (Hatton) 416 

Volume  125,  1918. 

Feb.  1,  p.  97  (Mohlman) 329 

Apr.  5,  pp.  297-8   (Anon.) 398 

Volume  128,  1919. 
Aug.  8,  p.  146   (Mickle) 367 

Volume  129,  1920. 
Jan.  2,  pp.  10-2  (Anon.) 508 

ENGINEERING. 

Volume  104,  1917.  Ref. 

July  6,  pp.  16-7  (Anon.) 292 

July  13,  pp.  49-51  (Caink) 295 

July  27,  pp.  99-100  (Anon.) 101 

Aug.  3,  pp.  118-9  (Anon.) 301 

Aug.  3,  p.  134  (Ardern) 296 

Sep.  14,  pp,  288-90  (Eddy) 217 

Sep.  28,  pp.  319-20  (Eddy) 217 

Oct.  26,  p.  444  (Anon.) 328 

Volume  105,  1918. 
Jan.  11,  pp.  40-1  (Anon.) 376 

ENGINEERING  NEWS. 

Volume   73,   1915.  Ref. 

Mar.  25,  p.  593  (Edit.) __  41 

Apr.  1,  pp.  647-8  (Bartow  et  al.)___  43 
Apr.  1,  p.  650  (News  item) 44 

Volume   74,   1915. 

July  15,  pp.  134-7   (Hatton) 58 

July  22,  pp.  164-71    (Baker) 60 

July  29,  pp.  214-7   (Fort) 61 

Sep.   16,  p.  571    (Pratt) 69 

Sep.  30,  pp.  667-8   (Hatton) 70 

Oct.  7,  p.  717  (Sands) _  73 

Nov.  4,  p.  899  (Edit.) 79 

Nov.   4,  pp.   904-6    (Nordell) 78 

Nov.  11,  p.  948   (Wilkinson) 80 

Dec.  2,  pp.  1096-7  (Bartow  et  al.)___  83 

Dec.  2,  p.  1101  (New,s  item) 86 

Dec.  9,  pp.  1146-7  (Fuller) 89 

Dec.  9,  p.  1148   (News  item) 90 


111 


The  Activated  Sludge  Process 


INDEX  OF  PERIODICALS  (Cont.) 


ENGINEERING  NEWS  (Cont.) 

Volume   75,   1916.  Ref. 

Jan.  27,  pp.  189-90  (Hatton) 110 

Feb.  10,  pp.  262-3  (Hatton) 122 

Feb.  10,  p.  293  (News  item) 123 

Feb.   17,  pp.  306-8   (Hatton) 122 

Mar.  16,  p.  503  (Hatton) 131 

Apr.  6,  pp.  671-2  (Pratt) 137 

Apr.  27,  pp.  798-800  (Hammond) 143 

Apr.  27,  pp.  809-10  (Edit.) 144 

May  18,  p.  932  (Lederer) 148 

Volume   76,   1916. 

July  6,  p.  37  (News  item) 163 

July  6,  p.  46  (News  item) 164 

July  20,  pp.  106-10  (Anon.) 170 

July  20,  p.  140  (News  item) 171 

Aug.  10,  p.  267  (Frank) 176 

Aug.  24,  p.   366   (Edit.) 178 

Aug.  24,  p.  380  (News  item) 179 

Sep.  28,  p.  624  (News  item) 184 

Oct.  5,  p.  663   (Edit.) 187 

Oct.  5,  pp.  665-6  (Copeland) 188 

Oct.  5,  p.  667  (Fuller) 189 

Oct.  12,  pp.  686-8  (Anon.) 193 

Nov.  2,  p.  856  (Nordell) 201 

Nov.  2,  p.  858  (Anon.) 202 

Nov.  9,  pp.  890-2    (Brosius) 208 

Nov.  23,  pp.  972-3  (Bartow  et  al.)__211 

Nov.  30,  p.  1056  (News  item) 214 

Dec.  7,  pp.  1061-6  (Pratt  et  al.) 219 

Dec.  14,  pp.  1124-8  (Pratt  et  al.) 219 

Volume  77,   1917. 

Jan.  4,  p.  18  (Requardt) 237 

Feb.  8,  pp.  236-8  (WilMford) 251 

Feb.  8,  p.  249  (Elrod) 252 

Mar.  1,  p.  373  (News  item) 257 

Mar.  1,  pp.  384-5   (Butcher) 258 

Mar.  8,  p.  406  (Edit.) 260 

Mar.  15,  p.  454  (News  item) 262 

ENGINEERING  NEWS-RECORD. 

Volume  78,   1917.  Ref. 

May  3,  pp.  255-6  (Coulter) 273 

May  31,  pp.  436-7  (Zimmele) 276 

June  14,  p.  535  (News  item) 281 

June  21,  pp,  594-6  (Anon.) 286 

June  21,  p.  604  (Literature  note) 287 

June  28,  pp.  628-9  (Nordell) 288 

Volume   79,   1917. 

July  5,  p.  33   (Noble) 291 

Aug.  9,  p.  269  (Anon.) 302 

Aug.  9,  pp.  269-70  (Anon.) 303 

Aug.  16,  p.  290  (Edit.) 306 

Aug.  16,  pp.  308-12   (Anon.) 305 

Sep.  13,  p.  522  (News  item) 313 

Sep.  20,  p.  551  (News  item) 316 

Oct.  25,  pp.  777-8  (Pearse) 327 


ENGINEERING  NEWS-RECORD 

(Cont.) 
Volume  79,  1917  (Cont.)         Ref. 

Nov.  1,  p.  817  (Edit.) 332 

Nov.  1,  pp.  829-30  (Mohlman) 329 

Nov.  1,  pp.  840-4  (Anon.) 333 

Nov.  15,  p.  940  (News  item) 339 

Nov.  22,  pp.  972-4  (Anon.) 347 

Nov.  22,  p.  987  (News  item) 348 

Nov.  29,  pp.  1009-10  (Anon.) 349 

Dec.  6,  pp.  1072-3  (Hatton  et  al.) 356 

Dec.  13,  p.  1085  (Edit.) 359 

Dec.  13,  p.  1127  (Anon.) 358 

Dec.  13,  p.  1128  (Anon.) 357 

Dec.  27,  pp.  1201-2  (Anon.) 363 

Volume  80,   1918. 

Jan.  31,  p.  205   (Anon.) __386 

Feb.  7,  p.  272   (Hatton) 389 

Feb.  21,  p.  382   (Anon.) 390 

Apr.  11,  p.  734  (News  item) 401 

Apr.  25,  p.  839  (News  item) 403 

June  20,  p.  1193  (Nasmith  et  al.) 405 

Volume   81,   1918. 

Sep.  12,  p.  514  (News  item) 421 

Oct.  31,  p.  785  (Edit.) 430 

Oct.  31,  pp.  806-8  (Anon.) 431 

Nov.  21,  pp.  930-1  (Clark) 434 

Dec.  5,  pp.  1034-6  (Winslow  et  al.)__459 

Volume   82,   1919. 
Jan.  2,  pp.  32-6  (Winslow  et  al.) 426 

Volume   83,   1919. 

Dec.  4,  pp.  948-52  (Wells) 484 

Dec.  16,  p.  920  (Anon.) 493 

Dec.  20,  p.  973  (Edit.) 496 

Dec.  20,  pp.  1003-4  (Anon.) 497 

Dec.  29,  p.  1063  (Anon.) 500 

Volume  84,   1920. 

Jan.  8,  p.  75  (Fugate) 510 

Mar.  11,  p.  511  (Hatton) 526 

Mar.  25,  p.  616  (Anon.) 531 

Apr.  15,  p.  754  (Fugate) 536 

Apr.  22,  pp.  819-23  (Lanphear) 540 

Apr.  29,  p.  873  (Anon.) 541 

May  20,  p.  989  (Edit.) 554 

May  20,  pp.  990-6  (Hatton) 555 

May  20,  p.  1034  (News  item) 556 

June  10,  pp.  1161-2  (Anon) 564 

June  24,  p.  1260  (Anon.) 567 

Volume  85,  1920. 

July  22,  pp.  145-6  (Edit.) 572 

Aug.  19,  pp.  344-9  (Gascoigne) 576 

Sep.  2,  pp.  457-8  (Anon.) 577 

Sep.  9,  pp.  490-2  (Eagles) 581 

Oct.  21,  p.  780  (Anon.) 588 

Oct.  21,  p.  815  (Anon.) 589 

Oct.  28,  p.  833  (News  item) 583 


112 


Indexes 


INDEX  OF  PERIODICALS  (Cont.) 


ENGINEERING  NEWS-RECORD 

(Cont.) 
Volume  85,  1920   (Cont.)        Ref. 

Nov.  4,  p.  889  (Anon.) 590 

Nov.  25,  p.  1018  (Edit.) 591 

Dec.  9,  p.  1125  (Anon.) 596 

Dec.  9,  p.  1128  (Anon.) 597 

Dec.  9,  pp.  1134-8  (Pearse) 598 

Dec.  30,  pp.  1286-8  (Orbison) 605 

ENGINEERING    RECORD. 

Volume   69,   1914.              Ref. 
Feb.  7,  p.  158  (Clark  et  al.) 6 

Volume  71,   1915. 

Mar.  6,  pp.  288-9  (Frank) 36 

Mar.  20,  pp.  367-8  (Clark) 40 

Apr.  3,  pp.  421-2  (Bartow  et  al.) 43 

Apr.  24,  pp.  521-2  (Frank  et  al.) 47 

June  19,  p.  784   (Coulter) 53 

Volume   72,    1915. 

July  3,  p.  23   (Requardt) 55 

Aug.  21,  p.  238  (Stevenson) 67 

Oct.  16,  pp.  481-4  (Hatton) 70 

Nov.  20,  p.  640  (Wilkinson) 82 

Dec.  18,  p.  768  (News  item) 97 

Volume   73,   1916. 

Jan.  1,  pp.  5-6  (Edit.) 103 

Jan.  22,  p.   121    (Carpenter) 109 

Jan.  29,  p.  160  (News  item) 112 

Feb.  19,  p.  255  (Hatton) 126 

Apr.  8,  p.  489  (Hatton  et  al.) 138 

Apr.  22,  p.  561  (News  item) 140 

Volume   74,   1916. 

July  15,  p.  91  (News  item) 169 

July  29,  pp.  137-8  (Harding  et  al.)_._173 

Oct.  7,  p.  428  (Edit.) 190 

Oct.  7,  pp.  444-5  (Copeland) 191 

Oct.  7,  p.  445  (Fuller) 189 

Oct.  7,  pp.  448-9  (Hammond) 192 

Nov.  4,  p.  557  (Anon.) 204 

Nov.  18,  p.  628  (Allin  et  al.) 210 

Nov.  25,  pp.  656-8  (Alvord  et  al.)___212 

Nov.  25,  p.  660  (Anon.) 213 

Dec.  2,  p.  695  (News  item) 214 

Dec.  23,  p.  784  (News  item) 226 

Volume   75,   1917. 

Jan.  6,  pp.  16-9   (Hatton) 239 

Jan.  20,  pp.  95-7  (Bartow  et  al.) 241 

Feb.  10,  pp.  228-9  (Anon.) 253 

Mar.  10,  p.  376  (Phelps) 248 

Mar.  10,  pp.  380-1  (Anon.) 261 

ENGINEERING  &  CONTRACTING. 

Volume   43,   1915.               Ref. 
Apr.  7,  p.  306  (Edit.) 45 

Apr.  7,  pp.  310-1  (Bartow  et  al.) 43 


ENGINEERING  &  CONTRACTING. 
(Cont.) 

Volume  44,   1915.  Ref. 

Oct.  27,  pp.  322-7   (Hatton) 75 

Oct.  27,  p.  322  (Edit.) 76 

Dec.  1,  pp.  433-4  (Bartow  et  al.) 83 

Dec.  1,  pp.  434-6  (Bartow  et  al.) 84 

Dec.  15,  p.  453  (Edit.) 94 

Volume  45,   1916. 

Feb.  2,  pp.  97-8   (Edit.) 116 

Feb.  2,  pp.  104-8  (Hatton) 117 

Mar.  1,  pp.  208-9  (Anon.) 129 

Mar.  15,  pp.  235-6  (Hatton) 131 

Apr.  26,  pp.  386-7  (Copeland) 141 

Apr.  26,  p.  388  (Lederer) 142 

June  28,  pp.  581-6  (Anon.) 155 

Volume  46,  1916. 

Nov.  8,  pp.  407-9   (Anon.) 207 

Dec.  13,  pp.  534-6  (Orbison  et  al.)__223 

Volume  47,   1917. 

Feb.  14,  pp.  154-7  (Anon.) 204 

Feb.  14,  -pp.  168-9  (Anon.) 254 

Volume  48,   1917. 

July  11,  pp.  28-30  (Anon.) 286 

Sep.  12,  pp.  217-20  (Anon.) 312 

Nov.  14,  pp.  386-8  (Anon.) 337 

Nov.  14,  pp.  390-1  (Anon.) 338 

Volume   49,   1918. 

Jan.  9,  pp.  36-7  (Anon.) 374 

Jan.  9,  pp.  38-9  (Anon.) 375 

Feb.  13,  pp.  165-8  (Anon.) 355 

Apr.  10,  p.  354  (Literature  note) 287 

Apr.  10,  pp.  368-72  (Anon.) 400 

June  12,  pp.  595-7  (Kershaw) 391 

Volume  50,   1918. 

July  10,  pp.  31-2  (Anon.) 406 

July  31,  pp.  122-3  (Anon.) 415 

Nov.  13,  p.  467  (Anon.) 433 

Volume  51,   1919. 

Apr.  30,  p.  465  (Anon.) 456 

May  14,  pp.  510-3  (Dorr  et  al.) 459 

Volume  52,   1919. 

July  9,  pp.  41-2  (Bartow  et  al.) 367 

Aug.  13,  pp.  196-7   (McFarland) 368 

Sep.  10,  p.  310  (News  item) 476 

Dec.  10,  p.  669  (Anon.) 491 

Volume  53,  1920. 

Jan.  14,  p.  39   (Hammond) 503 

Mar.  10,  pp.  280-3  (Anon.) 525 

Mar.  31,  pp.  357-9  (Ed  reprint) 508 

Mar.  31,  pp.  364-5   (Martin) 495 

May  12,  p.  543  (Anon.) 548 

May  12,  pp.  552-3  (Anon.) 549 

May  12,  p.  554  (Anon.) 550 

June  30,  p.  726  (Ed.  reprint) 519 

June  30,  pp.  736-8  (McGowan) 546 

June  30,  p.  762  (Anon.) 521 


113 


The  Activated  Sludge  Process 


INDEX  OF  PERIODICALS  (Cont.) 


JOUR.  AM.  LEATHER  CHEM.  ASSOC. 

Volume   11,   1916.  Ref. 

August,  pp.  441-9  (Eddy  et  al.) 160 

August,  pp.  450-3  (Rudnick  et  al) 161 

Volume   12,    1917. 

April,  pp.  128-35  (Ardern) 244 

May,  p.  199  (Lockett) 263 

July,  p.  320    (Hommon) 289 

October,  p.  563  (Bartow) 310 

Volume   13,   1918. 
April,  pp.  145-55  (Pearse) 371 

JOUR.  INDUS.  &  ENG.  CHEM. 

Volume    7,    1915.               Ref. 
April,  pp.  318-20  (Bartow  et  al.) 43 

Volume    8,    1916. 

January,  p.  15  (Bartow  et  al.) 83 

January,  pp.  17-20  (Bartow  et  al.) 84 

July,  pp.   642-3    (Copeland) 141 

July,  p.  643  (Fort) 156 

July,  p.  645   (Hendrick) 157 

July,  pp.  646-7  (Bartow  et  al.) 158 

July,  pp.  647-8   (Weston) 159 

July,  p.  648  (Eddy  et  al.) 160 

July,  pp.  651-2  (Rudnick  et  al.) 161 

July,  p.  652  (Lederer) 142 

July,  pp.  653-4  (Clark) 162 

Volume    9,    1917. 

April,  pp.   374-6    (Copeland) 267 

April,  pp.  399-400  (Hammond) 268 

September,  pp.  845-50  (Bartow) 310 

December,  pp.   1093-5   (Mohlman) 354 

Volume   10,   1918. 

May,  pp.  339-44  (Nasmith  et  al.) 405 

May,  p.  400  (Rudnick) 406 

Volume   12,   1920. 
May,  p.  419  (Anon.) 543 

JOUR.   SOC.   CHEMICAL    INDUSTRY. 
Volume   33,   1914.  Ref. 

May  3Q,  pp.  523-39  (Ardern  et  al.)___  9 
Dec.  15,  pp.  1122-4  (Ardern  et  al.)__  23 

Dec.   15,  pp.   1124-30   (Melling) 24 

Dec.  15,  p.  1170  (J.  &  A.  pat.) 10 

Volume  34,   1915. 

Feb.  27,  p.  197  (J  &  A  pat.) 5 

Mar.  15,  p.  244  (J  &  A  pat.) 3 

May  15,  p.  508  (Bartow  et  al.) 43 

June  15,  p.  632  (J  &  A  pat.) 11 

June  30,  p.  680  (Frank  pat.) 48 

July  31,  p.  814  (Naylor  pat.) 13 

Sep.  30,  pp.  937-43  (Ardern  et  al.)__  71 

Sep.  30,  p.  978  (Naylor  pat.) 14 

Dec.  31,  p.  1269  (Beckett  pat.)___.__  16 
Dec.  31,  p.  1269  (Naylor  pat.) 20 


JOUR.    SOC.   CHEMICAL   INDUSTRY. 
(Cont.) 

Volume  35,   1916.  Ref. 

Feb.  15,  pp.  153-5  (Ardern  et  al.)___124 
Feb.  15,  p.  195  (J  &  A  pat.)__17,  18,  28 

Feb.  15,  p.  195  (Naylor  pat.) 27 

Feb.  29,  p.  272  (J  &  A  pat.) 15 

Mar.  15,  p.  326  (J  &  A  pat.) 33 

Mar.  15,  p.  326  (Cooper  pat.) 37 

Apr.  15,  p.  434   (Mottram  pat.) 34 

Apr.  15,  p.  434  (Naylor  pat.) 57 

Apr.  29,  p.  30  Sup.  (Bowes  pat.  Ap.)_139 

May  15,  p.  521   (Mottram  pat.) 39 

May  15,  p.  552  (Bartow  et  al.) 84 

May  15,  p.  555  (Bartow  et  al.) 83 

May  31,  p.  615  (Naylor  pat.) 56 

June  15,  p.  647  (Mumford) 152 

Aug.  31,  p.  904  (Copeland) 141 

Aug.  31,  p.  904   (Weston) 159 

Aug.  31,  p.  904  (Rudnick  et  al.) 161 

Aug.  31,  p.  904   (Clark) 162 

Aug.  31,  p.  905  (Eddy  et  al.) 160 

Sep.  15,  p.  55  Sup.  (G  &  H  pat.  Ap.)181 
Oct.  31,  p.  1074  (Fowler  &  M.  pat.)__  51 
Nov.  15,  p.  1129  (Long  pat.) 74 

Volume  36,   1917. 

Jan.  15,  p.  44  (Rideal) 218 

Jan.  31,  pp.  65-8  (Ardern  et  al.) 244 

Feb.   15,  p.   160   (Martin  pat.) 92 

Feb.  28,  p.  201  (Nordell  pat.) 225 

Mar.  15,  pp.  264-9   (Lockett) 263 

Apr.  30,  p.  471  (J  &  A  pat.) 165 

May  15,  pp.  517-8  (Copeland) 267 

May  15,  p.  519  (Ames  pat.) 127 

June  15,  p.  611  (Caink  pat.) 149 

July  31,  pp.  822-30  (Ardern) 296 

Aug.  31,  p.  938  (Caink) 295 

Aug.  31,  p.  79  Sup.  (L  &  H-S  pat.  Ap.)304 

Sep.  15,  pip.  977-8  (Ames  pat.) 255 

Oct.  15,  p.  95  Sup.  (G  &  H  pat.  Ap.)_314 

Nov.  15,  p.  1146  (Bartow) 310 

Dec.  15,  p.  1247  (Ames  pat.) 194 

Volume   37,   1918. 

Jan.  31,  pp.  38A  (Jones  pat.) 343,  344 

Feb.  15,  p.  71A   (Dienert) 340 

Feb.  15,  p.  72A  (Naylor  pat.) 221 

Feb.  15,  p.  72A  (J  &  A  pat.) 222 

Feb.  28,  p.  106A  (Cronin) 320 

Apr.  15,  p.  193A  (J  &  A  pat.) 256 

Apr.  15,  p.  193A  (Moor  pat.) 383 

Apr.  15,  p.  193A  (Mulloy  pat.) 384 

Apr.  15,  p.  193A   (Noble  pat.) 385 

Apr.  15,  p.  196A  (G  &  H  pat.  Ap.)__396 

June  29,  p.  348A  (Pearse) 371 

July  15,  p.  384A  (Nasmith  et  al.)___405 
Aug.  15,  p.  440A  (Clifford  pat.)_____274 

Aug.  15,  p.  440A  (Ames  pat.) 285 

Aug.  31,  p.  484A  (Caink  pat.)- 294 

Oct.  15,  p.  603A  (Moore  pat.) 411,  412 

Oct.  15,  p.  604A  (Buckley  pat.) 410 


114 


Indexes 


INDEX  OF  PERIODICALS  (Cont.) 


JOUR.    SOC.   CHEMICAL   INDUSTRY. 

(Cont.) 

Volume   38,   1919.              Ref. 
Jan.  15,  p.  4R  (Anon.) 440 

Jan,  31,  p.  53A  (Nordell  pat.) 427 

Feb.  15,  p.  96A  (H  &  H  pat.  Ap.) 450 

Feb.  28,  p.  116A  (Jones  pat.) 428,  435 

Mar.  15,  p.  157A  (Brosius  pat.) 438 

Mar.  15,  p.  157 A  (Rein  et  al.  pat.)___439 

Mar.  31,  p.  197A  (J  &  A  pat.) 308 

Sep.  16,  p.  497A  (Clifford  pat.) 275 

S0p.  30,  p.  694 A  (Buckley  pat.) 413 

Oct.  31,  p.  790A  (J  &  A  pat.) 418 

Nov.  15,  p.  843A  (J  &  A  pat.) 419 

Nov.  30,  p.  876A  (J  &  A  pat.) 404 

Nov.  30,  p.  884 A  (H  &  H  pat.  Ap.)__483 
Dec.  31,  p.  961A  (Stott  &  J.  pat.)___407 

Dec.  31,  p.  968A  (Mumford  pat.) 490 

Volume  39,   1920. 

Feb.   28,  p.   171A    (Courmont) 509 

Mar.  15,  pp.  60-4T  (Ardern) 527 

Apr.  30,  p.  145R  (Brenehley  et  al.)__538 
May  15,  p.  347 A  (Whyte  et  al.  pat.)_455 

May  15,  p.  347A  (Gambler) 528 

May  15,  p.  347A  (Dienert) 530 

May  31,  pp.  382-3A  (Dienert) 535 

June  15,  p.  423A  (Courmont) 539 

June  15,  p.  424A  (Dienert) 545 

June   15,  p.  434 A   (A.   S.  Lt'd.  pat.) 

551,  552 

June  30,  p.  465A   (Courmont) 547 

July   15,  pp.   177-82T    (Brenchley  et 

al.) 538 

July  31,  p.  525A  (Ames  pat.) 466 

July  31,  p.  525A  (Cambier) 563 

July  31,  p.  526A  (Jones  pat.) 561 

Aug.  16,  pp.  556-7A  (Cambier) 570 

Aug.  16,  p.  557 A  (Stott  &  J.  pat.)___566 
Aug.  31,  p.  581A  (Adams) 473 

MUNICIPAL  ENGINEERING. 

Volume   47,   1914.               Ref. 
December,  pp.  427-36  (Hammond) 7 

Volume   49,   1915. 
August,  pp.  68-9   (Wynne-Roberts)--  54 

Volume  50,   1916. 

January,  pp.  6-8  (Anon.) 105 

February,  p.  73  (Anon.) 115 

Volume  51,   1916. 

September,  p.  105  (News  item) 179 

December,  pp.  234-5   (Anon.) 215 

Volume   53,   1917. 

September,  p.  108  (Fales) 311 

October,  pp.  148-9  (Bartow) 319 

December,  pp.  243-6   (Anon.) 353 

Volume  54,  1918. 

February,  pp.  78-9   (Anon.) 387 

June,  pp.  244-9  (Allen) 408 


MUNICIPAL    &    COUNTY    ENG'RG. 

Volume  55,   1918.  Ref. 

August,  pp.   67-70    (Hatton) 416 

September,  pp.  106-8  (Fuller) 420 

November,  pp.  173-5  (Winslow  et  al.)432 

Volume   57,   1919. 
September,  pp.  123-5  (Fuller) 460 

Volume  58,   1920. 
February,  pp.  71-5    (Stein) 517 

Volume  59,   1920. 
August,  pp.  58-9  (Horton) 574 

MUNICIPAL  JOURNAL. 

Volume   36,   1914.               Ref. 
Feb.   19,  pp.  233-9   (Hammond) 7 

Volume   38,   1915. 

Apr.  15,  pp.  504-5  (Bartow  et  al.)__  43 
Apr.  15,  p.  509  (Edit.) 46 

Volume   39,   1915. 

Aug.  19,  p.  257  (Edit.) 66 

Nov.  18,  p.  776  (Anon.) 81 

Volume   40,   1916. 
Feb.  10,  pp.  199-200   (Duckworth)—  93 

Apr.  27,  pp.  585-8  (Anon.) 146 

June  8,  pp.  785-7   (Hatton) 153 

June  15,  pp.  824-5,  830  ( Hatton)  ___153 
June  15,  p.  833    (Edit.) 154 

Volume   41,   1916. 
Sep.  28,  pp.  383-4  (Edit.)..  __185 

Oct.  12,  p.  446  (Copeland) 188 

Oct.   19,  pp.  480-3    (Anon.) 196 

Oct.  26,  pp.  510-3  (Anon.) 196 

Nov.  30,  p.  677  (News  item) 214 

Volume  42,   1917. 

Jan.  4,  pp.  11-2  (Edit.) 238 

Feb.  8,  pp.  196-7  (Anon.) 250 

Mar.  8,  pp.  333-5  (Zimmele) 259 

Apr.  12,  p.  526  (Alvord  et  al.) 269 

Volume   43,   1917. 

Sep.  20,  p.  291  (News  item) 315 

Oct.  18,  pp.  377-9  (Anon.) 322 

Oct.  18.  p.  381  (Edit.) 323 

Oct.  18,  p.  382  (Hatton) 324 

Nov.  22,  p.  508  (Anon) 345 

Nov.  22,  p.  510  (Anon.) 346 

Volume   44,   1918. 

Jan.  5,  pp.  14-6  (Anon.) 355 

Jan,  19,  p.  59  (News  item) 378 

Mar.  16,  pp.  223-5  (Anon.) 395 

Volume   45,   1918. 

July  29,  p  84  (News  item)__  __414 

__426 
__426 
-426 


Oct.  12,  pp.  280-2  (Winslow  et  al. 
Oct.  19,  pp.  297-9  (Winslow  et  al. 
Oct.  26,  p.p  321-2  (Winslow  et  al. 


115 


The  Activated  Sludge  Process 


INDEX  OF  PERIODICALS  (Cont.) 


MUNIC.  JOURNAL  PUBLIC  WORKS. 

Volume  46,   1919.  Ref. 

Mar.  29,  p.  225  (Anon.) 457 

Apr.  12,  p.  266   (Anon.) 462 

May.  17,  p.  349  (Edit.) 468 

May  17,  p.  356   (Anon.) 469 

Volume   47,   1919. 

Sep.  27,  pp.  199-200  (Anon.) 477 

Oct.  4,  pp.  210-3  (Anon.) 479 

Oct.  11,  p.  219  (Edit.) 480 

Oct.  11,  pp.  226-7  (Anon.) 479 

Nov.  8,  pp.  278-80  (Wells) 484 

Dec.  6,  pp.  345-6  (Clark) 362 

PUBLIC  WORKS. 

Volume  48,   1920.  Ref. 

May  22,  p.  446  (Anon.) 559 

May  22,  p.  447  (Edit.) ___560 

June  29,  pp.  536-8  (Hatton) 555 

Volume  49,   1920. 

Sep.  18,  pp.  251-3  (Pearse) 533 

Oct.  23,  pp.  385-7  (Anon.) 589 

Nov.  13,  pp.  461-3  (Anon.) 589 

Nov.  27,  pp.  504-6  (Weston) 592 

Dec.  18,  pp.  567-9  (Anon) 602 

THE  SURVEYOR. 

Volume  45,   1914.  Ref. 

Mar.  20,  pp.  504-6  (Fowler) 8 

Apr.  10,  p.  610  (Ardern) 9 

Volume  46,   1914. 

July  24,  pp.  113-4  (Edit.) 12 

Nov.  22,  pp.  592-4  (Naylor) 19 

Dec.  11,  p.  674  (Edit.) 21 

Dec.  11,  pp.  581-2  (Duckworth) 22 

Dec.  18,  p.  701  (Edit.) 25 

Dec.  18,  pp.  714-7  (Ardern) 26 

Dec.  25,  p.  754  (Discussion) 29 

Volume   47,   1915. 

Jan.  1,  p.  8  (Kersihaw) 31 

Mar.  26,  p.  449  (Edit.) 42 

May  21,  p.  642  (Bartow  et  al.) 43 

June  4,  p.  693  (Frank  et  al.) 50 

Volume  48,   1915. 

July  16,  pp.  74-6  (Wilson) 59 

July  30,  p.  129  (Edit.) 62 

July  30,  pp.  132-3  (Wakeford) 63 

Aug.  6,  pp.  143-6  (Discussion) 65 

Aug.  20,  p.  211  (Wynne-Roberts)—  54 

Sep.  3,  p.  253  (Edit.) 68 

Sep.  3,  pp.  258-61  (Hatton) 58 

Oct.  29,  p.  445  (Edit.) 77 

Oct.  29,  pp.  450-4  (Ardern  et  al.) 71 

Dec.  3,  p.  562  (Edit.) 87 

Dec.  3,  pp.  564-7  (Hatton) 90 

Dec.  10,  p.  604   (Fowler) 91 

Dec.  17,  pp.  629-30  (Discussion) 95 

Dec.  24,  p.  645  (Edit.) 98 

Dec.  24,  pp.  648-52  (Duckworth) 93 


THE  SURVEYOR   (Cont.) 

Volume   49,   1916.  Ref. 

Jan.  21,  p.  51  (Edit.) 107 

Jan.  21,  pp.  55-6  (Cooper) 108 

Jan.  28,  p.  126  (Jones  &  Attwood)__lll 

Feb.  4,  p.  143   (Edit.) 119 

Feb.  4,  pp.  148-51  (Fowler) 120 

Feb.  25,  pp.  233-4   (Fuller) 89 

Feb.  25,  p.  234  (Edit.) 128 

Mar.  3,  pp.  255-7  (Hammond) 130 

Mar.  17,  pp.  308-9  (Hatton) 117 

Mar.  31,  pp.  352-4  (Duckworth) 133 

Apr.  14,  pp.  405-6   (Fowler) 121 

May  12,  p.  480  (Edit.) 147 

May  12,  p.  486  (Hatton  et  al.) 138 

Volume  50,   1916. 

July  14,  pp.  29-30  (Barwise) 166 

July  14,  pp.  33-4  (Discussion) 167 

July  14,  pp.  40-2  (Haworth) 168 

July  28,  p.  83  (Edit.) 172 

Aug.  4,  p.  93  (Edit.) 174 

Aug.  25,  pp.  160-3  (Anon.) 170 

Sep.  15,  pp.  238-41   (Eddy) 136 

Sep.  15,  p.  247  (Edit.) 183 

Sep.  29,  pp.  282-4  (Eddy  et  al.) 160 

Oct.  27,  pp.  373-4   (Edit.) 198 

Oct.  27,  pp.  379-80    (Anon.) 199 

Nov.  3,  pp.  400-1  (Hammond) 192 

Nov.  10,  pp.  430-2   (Edit.) 209 

Nov.  17,  pp.  453-5  (Hammond) 195 

Nov.  24,  pp.  479-80  (Hammond) 195 

Dec.  1,  pp.  504-6  (Eddy) 203 

Volume  51,   1917. 

Jan.  5,  pp.  4-5  (Nasmith) __216 

Jan.  5,  p.  6  (Anon.) 211 

Jan.  26,  pp.  80-2  (Edit.) 242 

Jan.  26,  p.  108  (News  item) 243 

Feb.  2,  p.  144  (Caink) 247 

Mar.  9,  pp.  254-5  (Phelps) 248 

Mar.  23,  p.  297  (Edit.) 264 

Mar.  23,  pp.  298-9   (Ardern) 244 

Mar.  23,  pp.  299-300  ( Discussion) ___265 

Apr.   13,  p.  359    (Edit.) 270 

Apr.  13,  pp.  370-2  (Eddy) 217 

May  18,  p.  458  (Adams) 272 

June  1,  pp.  506-7  (Coulter)___ 273 

June  15,  pp.  544-5  (Edit.) 283 

June  15,  pp.  546-8  (Caink) 282 

June  15,  p.  549  (Jones  &  Attwood)— 284 

Volume   52,   1917. 

July  6,  p.  10  (News  item) 293 

July  13,  p.  40  (Barwise) 297 

July  20,  pp.  45-6  (Edit.) 298 

July  20,  pp.  51-5  (Caink) 295 

July  20,  p.  67  (Discussion). 299 

July  27,  pp.  87-8  (Caink) 300 

Aug.  17,  pp.  137-8  (Edit.) 307 

Aug.  17,  pp.  140-2  (Ardern) 296 


116 


Indexes 


INDEX  OF  PERIODICALS  (Cont.) 


THE  SURVEYOR   (Cont.) 
Volume  52,  1917   (Cont.) 

Sep.  21,  p.  246  (Edit.) 318 

Sep.  21,  p.  252  (Zimmele) 276 

Sep.  21,  p.  253  (Edit.) 317 

Oct.  19,  p.  333  (Edit.) 325 

Oct.  19,  p.  342  (Anon.) 305 

Nov.  23,  p.  445  (Hatton) 324 

Nov.  30,  p.  471  (Caink) 350 

Dec.  21,  p.  527  (Edit.) 361 

Dec.  21,  p.  528  (Anon.) 321 

Dec.  28,  p.  552  (Discussion) 364 

Volume  53,  1918. 

Jan.  4,  pp.  4-5  (Anon.) 373 

Jan.  18,  pp.  42-4  (Young  et  al.) 372 

Jan.  18,  pp.  46-8  (Anon.) 375 

Jan.  25,  pp.  71-3  (Edit.) 380 

Jan.  25,  p.  106  (News  item) 381 

Jan.  25,  pp.  114-5  (Anon.) 382 

Jan.  25,  pp.  117-9   (Discussion) 379 

Feb.  1,  p.  125  (Edit.) 388 

Feb.  22,  p.  197  (Kershaw) 391 

Mar.  8,  p.  229  (Edit.) 393 

Mar.  8,  pp.  232-3   (Hatton) 333 

Mar.  15,  pp.  254-5  (Hatton) 333 

Apr.  5,  p.  314  (Anon.) 399 

June  28,  p.  457  (Edit.) 409 

Volume   54,   1918. 

Sep.  13,  p.  131  (Bade) 422 

Sep.  20,  p.  139  (News  item) 423 

Oct.  4,  p.  166  (News  item) 425 

Oct.  25,  pp.  195-6  (Martin) 429 

Nov.  29,  p.  255   (Anon.) 436 

Volume   55,   1919. 

Jan.  10,  pp.  17-8  (Anon.) 449 

Jan.  31,  pp.  66-9  (Edit.) 451 

Jan.  31,  p.  105  (Trade  note) 452 

Feb.  14,  p.  143  (Clark) 434 

Apr.  11,  p.  282  (News  item) 461 

Apr.  18,  p.  298  (News,  item) 463 

June  6,  pp.  419-21  (Dorr  et  al.) 459 

June  20,  p.  470  (News  item) 470 

Volume   56,   1919. 

July  18,  p.  49  (Anon.) 472 

Sep.  5,  p.  146  (News  item) 475 

Oct.  17,  pp.  225-6  (Godfrey) 474 


THE  SURVEYOR   (Cont.) 
Volume  56,  1919   (Cont.) 

Oct.  31,  p.  258  (Bottomly) 481 

Nov.  14,  p.  293  (Anon.) 486 

Dec.  5,  p.  366  (Anon.)__ 489 

Dec.  19,  p.  398  (Edit.) 494 

Dec.  19,  pp.  401-2   (Martin) 495 

Dec.  26,  pp.  417-8  (Anon.) 499 

Dec.  26,  p.  419  (Martin) 495 

Volume   57,   1920. 

Jan.  2,  pp.  8-9  (Anon.) 507 

Jan.  9,  pp.  19-21  (Nasmith) 492 

Jan.  9,  p.  27  (News  item) 511 

Jan.  30,  pp.  75-7  (Edit.) 514 

Jan.  30,  p.  119  (Trade  note) 516 

Feb.  27,  p.  199  (Edit.) 519 

Feb.  27,  pp.  201-2  (Anon.)_. 520 

Feb.  27,  p.  205  (Anon.) 521 

Feb.  27,  p.  208  (News  item) 522 

Mar.  5,  p.  216  (Edit.) 523 

Mar.  5,  p.  222  (Anon.) 524 

Mar.  12,  p.  244  (Hatton) 500 

Apr.  9,  p.  308  (Clark) 534 

Apr.  16,  p.  328  (Clifford) 537 

May  7,  pp.  405-7  (McGowan) 546 

May  14,  pp.  426-7  (Discussion) 553 

,May  21,  p.  440  (Anon.) 557 

May  21,  p.  446  (Martin) 558 

May  28,  p.  469  (News  item) 562 

Volume  58,   1920. 

July  9,  pp.  21-3  (Hatton) 555 

July  9,  p.  23  (Anon.) 571 

July  16,  pp.  48-9  (Hatton) 555 

July  23,  p.  64  (News  item) 573 

Sep.  17,  p.  188  (News  item) 582 

Oct.  1,  p.  221  (News  item) 583 

Oct.  8,  p.  225   (Edit.) 586 

Oct.  29,  p.  292  (Godfrey) 578 

Dec.  3,  p.  374  (Edit.) 593 

Dec.  3,  p.  375  (Anon.) 594 

Dec.  3,  p.  380  (Anon.) 595 

Dec.  10,  pp.  397-8  (Makepeace) 599 

Dec.  17,  p.  412  (Farmer) 600 

Dec.  17,  pp.  413-4  (Anon.) 601 

Dec.  24  pp.  427-8  (Ardern) 527 

Dec.  24,  p.  430  (Discussion) 600 


UNIVERSITY  OF  CALIFORNIA 
DEPARTMENT  OF  CIVIL  ENGINEERING 

PHRKELEY.  CALIFORNIA 

117 


GENERAL  FILTRATION  COMPANY,  INC. 
GENERAL  OFFICES  -  ROCHESTER,  N.  Y. 
WORKS  -  -  EAST  ROCHESTER 

MAKERS    OF    FILTROS 


RETURN  TO  the  circulation  desk  of  any 

University  of  California  Library 

or  to  the 

NORTHERN  REGIONAL  LIBRARY  FACILITY 
Bldg.  400,  Richmond  Field  Station 
University  of  California 
Richmond,  CA  94804-4698 

ALL  BOOKS  MAY  BE  RECALLED  AFTER  7  DAYS 
2- month  loans  may  be  renewed  by  calling 

(510)642-6753 
1-year  loans  may  be  recharged  by  bringing  books 

to  NRLF 
Renewals    and    recharges    may    be    made    4    days 

prior  to  due  date 

DUE  AS  STAMPED  BELOW 


MAY  1  0  fflfi 


20,000  (4/94) 


I3DA9 


7f4 


D 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


